English Vocabulary · Grade 9 Live Review Preview
9th Grade Vocabulary Words
Ninth grade marks the transition to high-school reading and writing across literature, argument, research, biology, physical and Earth science, algebra, computing, world history, civics, and geography. This level develops precise academic and domain-specific vocabulary while strengthening context, nuance, source evaluation, figurative language, and evidence-based communication.
This independently authored 800-word beta curriculum is arranged in twenty-three pages of up to thirty-five words. Pages containing words 1–500 include five cloze questions drawn only from that enhanced range; words 501–800 remain fully visible and editable as list pages while the expanded practice layer is developed. Each row includes a subject-field label and an editable word-study note about a transparent affix, compound structure, capitalization, or dictionary base form. The cited Grade 9 resources calibrate difficulty and study skills only; all learner-facing definitions, examples, quizzes, and descriptions are original KSSR copy.
Please note: the vocabulary lists for grades 9~11 have been selected to ensure no overlap with the previous grade level. If the words are too specialized or difficult for you, please go back to grade levels 4~8 and review the words on those pages.
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| # | Word | Details | Meaning | Sample sentence |
|---|---|---|---|---|
| 316 | solution concentration | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: solution + concentration. Study the complete expression as one field-specific unit. | the amount of dissolved substance in a given amount of solution | Evaporation increased the solution concentration. |
| 317 | molarity | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Suffix focus: -ity commonly forms a noun naming a quality, state, or condition. | solution concentration measured in moles of solute per liter of solution | The beaker contained a molarity of 0.5 moles per liter. |
| 318 | pH scale | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: pH + scale. Study the complete expression as one field-specific unit. | a numerical scale describing how acidic or basic an aqueous solution is | Pure water is near 7 on the pH scale. |
| 319 | acid-base indicator | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: acid + base + indicator. Study the complete expression as one field-specific unit. | a substance whose color changes over a range of acidity or basicity | Litmus is an acid-base indicator that turns red in acid. |
| 320 | electrolyte | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Base-form focus: electrolyte is the dictionary headword; compare its inflected or derived forms in context. | a substance that forms ions in solution and allows the solution to conduct electricity | Dissolved salt is an electrolyte. |
| 321 | nonelectrolyte | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Prefix focus: non- means not or without. | a substance that dissolves without forming enough ions to conduct electricity | Sugar is a nonelectrolyte in water. |
| 322 | oxidation number | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: oxidation + number. Study the complete expression as one field-specific unit. | a bookkeeping value representing an atom's apparent charge in a compound | Oxygen usually has an oxidation number of negative two. |
| 323 | redox reaction | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: redox + reaction. Study the complete expression as one field-specific unit. | a reaction involving electron transfer and changes in oxidation numbers | Rusting is a redox reaction in which iron loses electrons. |
| 324 | electron transfer | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: electron + transfer. Study the complete expression as one field-specific unit. | movement of one or more electrons from one atom or species to another | Electron transfer occurs from zinc to copper ions in the cell. |
| 325 | synthesis reaction | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: synthesis + reaction. Study the complete expression as one field-specific unit. | a chemical reaction in which simpler substances combine to form a more complex product | A synthesis reaction joins hydrogen and oxygen to form water. |
| 326 | decomposition reaction | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: decomposition + reaction. Study the complete expression as one field-specific unit. | a chemical reaction in which one compound breaks into simpler substances | Heating calcium carbonate causes a decomposition reaction. |
| 327 | single-replacement reaction | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: single + replacement + reaction. Study the complete expression as one field-specific unit. | a reaction in which one element replaces another element in a compound | Zinc replacing hydrogen in acid is a single-replacement reaction. |
| 328 | double-replacement reaction | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: double + replacement + reaction. Study the complete expression as one field-specific unit. | a reaction in which ions from two compounds exchange partners | The two clear solutions undergo a double-replacement reaction and form a solid. |
| 329 | precipitation reaction | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: precipitation + reaction. Study the complete expression as one field-specific unit. | a solution reaction that produces an insoluble solid | Mixing silver nitrate and sodium chloride causes a precipitation reaction. |
| 330 | net ionic equation | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: net + ionic + equation. Study the complete expression as one field-specific unit. | an equation showing only the particles that directly change during a solution reaction | The net ionic equation omits ions that remain unchanged. |
| 331 | scalar | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Base-form focus: scalar is the dictionary headword; compare its inflected or derived forms in context. | a quantity described by size alone without direction | Temperature is a scalar. |
| 332 | vector | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Base-form focus: vector is the dictionary headword; compare its inflected or derived forms in context. | a quantity described by both size and direction | Velocity is a vector because its direction matters. |
| 333 | vector magnitude | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: vector + magnitude. Study the complete expression as one field-specific unit. | the size or numerical length of a vector | The arrow's length represents the vector magnitude. |
| 334 | instantaneous velocity | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: instantaneous + velocity. Study the complete expression as one field-specific unit. | an object's speed and direction at one particular moment | The speedometer approximates the car's instantaneous velocity. |
| 335 | average acceleration | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: average + acceleration. Study the complete expression as one field-specific unit. | change in velocity divided by the time over which the change occurs | The runner's average acceleration was greatest during the first two seconds. |
| 336 | linear momentum | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: linear + momentum. Study the complete expression as one field-specific unit. | the product of an object's mass and velocity | A moving truck has more linear momentum than a bicycle at the same speed. |
| 337 | impulse | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Base-form focus: impulse is the dictionary headword; compare its inflected or derived forms in context. | force multiplied by the time it acts, equal to the resulting change in momentum | An air bag extends the stopping time and changes the passenger's momentum with a smaller impulse force. |
| 338 | rotational inertia | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: rotational + inertia. Study the complete expression as one field-specific unit. | an object's resistance to a change in its rotational motion | Moving mass farther from an axis increases rotational inertia. |
| 339 | force equilibrium | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: force + equilibrium. Study the complete expression as one field-specific unit. | a state in which forces balance and the net force is zero | A hanging lamp at rest is in force equilibrium. |
| 340 | frictional force | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: frictional + force. Study the complete expression as one field-specific unit. | a force resisting motion or attempted motion between touching surfaces | The frictional force between shoes and the floor prevents slipping. |
| 341 | gravitational force | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: gravitational + force. Study the complete expression as one field-specific unit. | the attractive force between objects with mass | Earth's gravitational force pulls the ball downward. |
| 342 | normal force | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: normal + force. Study the complete expression as one field-specific unit. | a support force exerted perpendicular to a contacting surface | The table's normal force balances the book's weight. |
| 343 | applied force | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: applied + force. Study the complete expression as one field-specific unit. | a push or pull exerted on an object by a person or another object | The worker's applied force moved the crate across the floor. |
| 344 | tension force | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: tension + force. Study the complete expression as one field-specific unit. | a pulling force transmitted through a taut rope, string, or cable | The cable's tension force supports the elevator. |
| 345 | free-body diagram | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: free + body + diagram. Study the complete expression as one field-specific unit. | a sketch showing all external forces acting on one chosen object | The free-body diagram includes gravity, support, and friction. |
| 346 | Newton's first law | proper noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: Newton's + first + law. Study the complete expression as one field-specific unit. | the law that motion remains unchanged unless a net external force acts | Newton's first law explains why a puck keeps sliding on nearly frictionless ice. |
| 347 | Newton's second law | proper noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: Newton's + second + law. Study the complete expression as one field-specific unit. | the law relating net force to mass and acceleration | Newton's second law predicts greater acceleration when the same mass receives a larger force. |
| 348 | Newton's third law | proper noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: Newton's + third + law. Study the complete expression as one field-specific unit. | the law that interacting objects exert equal and opposite forces on each other | Newton's third law pairs the swimmer's push on water with water's push on the swimmer. |
| 349 | conservation of momentum | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: conservation + of + momentum. Study the complete expression as one field-specific unit. | the principle that total momentum remains constant in an isolated system | Conservation of momentum explains the motion of two skaters who push apart. |
| 350 | elastic collision | noun StudyField: Grade 9 physical, Earth, and environmental-science term Word study: Term structure: elastic + collision. Study the complete expression as one field-specific unit. | a collision in which both total momentum and total kinetic energy are conserved | An ideal elastic collision allows two hard spheres to rebound without losing kinetic energy. |
Vocabulary reading and practice
Forces and Solutions
Reading practice for pages 10–12. Five relevant words are highlighted.
English reading
A beaker rests on a scale while gravitational force pulls it downward and normal force from the scale pushes upward. Inside, a precipitation reaction forms a solid from two clear solutions. The chemist describes each solution concentration with molarity, the number of moles of dissolved substance per liter of solution.
Translation
Reading comprehension
1. Which force pulls the beaker downward?
Gravitational force pulls it downward.
2. What forms during a precipitation reaction?
A solid forms from the solutions.
3. What does molarity measure?
Molarity measures moles of solute per liter of solution.
Vocabulary quiz
Complete 5 review questions for this page.
1. Earth's ___ pulls the ball downward.
Answer: gravitational force
2. Evaporation increased the ___.
Answer: solution concentration
3. Mixing silver nitrate and sodium chloride causes a ___.
Answer: precipitation reaction
4. The table's ___ balances the book's weight.
Answer: normal force
5. The beaker contained a ___ of 0.5 moles per liter.
Answer: molarity
Vocabulary chart page
This page focuses on the word chart. Reading passages appear once in each three-page group, while cloze quizzes remain in the established enhanced range for this level.
Sources and curriculum references
These references guide selection and calibration. Definitions, sample sentences, readings, questions, and teaching notes are independently written and reviewed.
- GreatSchools: 9th Grade Vocabulary Words
- Victoria University of Wellington: Coxhead Academic Word List
- Common Core: Language Standards for Grades 9–10
- Common Core: Science and Technical Subjects, Grades 9–10
- WikDict downloadable bilingual dictionaries
- Kaikki.org / Wiktextract machine-readable Wiktionary data
- Language-Learning-decks public flashcard datasets
- SBBIC English-to-Khmer Dictionary
- English–Khmer Dictionary Dataset (machine-generated Khmer fallback; human review required)
- PanLex meanings snapshot (direct CC0 gap candidates; human review required)
- Cambridge bilingual dictionaries (individual editorial sense checks)
- Collins English–Hindi Dictionary (individual editorial checks)
- Hindwi and Rekhta dictionaries (individual Hindi/Urdu checks)
- National Institute of Korean Language: Basic Korean Dictionary
- JMdict/EDRDG Japanese dictionary project
- CC-CEDICT Chinese dictionary project
- VDict Vietnamese Dictionary (individual editorial check)
- Google Translate (machine-assisted lesson-reading draft; fluent review required)
- Kuperman et al.: Age-of-acquisition ratings for 30,000 English words
- The Princeton Review, Word Smart (2006 and 2012 editions; bibliographic calibration only).

