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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Words 421–455 of 800
#	Word	Details	Meaning	Sample sentence
421	factorization	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Suffix focus: -ization forms a noun for a process of making or becoming.	the rewriting of an expression as a product of factors	Factorization changes x squared minus nine into the product of x minus three and x plus three.
422	greatest common factor	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: greatest + common + factor. Study the complete expression as one field-specific unit.	the largest factor shared by two or more numbers or terms	Six is the greatest common factor of eighteen and twenty-four.
423	difference of squares	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: difference + of + squares. Study the complete expression as one field-specific unit.	an expression in the form of one square minus another square	The difference of squares x squared minus sixteen factors into two binomials.
424	perfect square trinomial	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: perfect + square + trinomial. Study the complete expression as one field-specific unit.	a three-term expression produced by squaring a binomial	The expression x squared plus six x plus nine is a perfect square trinomial.
425	radical expression	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: radical + expression. Study the complete expression as one field-specific unit.	an expression containing a root symbol	The radical expression square root of fifty simplifies to five square root of two.
426	rational expression	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: rational + expression. Study the complete expression as one field-specific unit.	a quotient of polynomial expressions with a nonzero denominator	The rational expression is undefined when its denominator equals zero.
427	absolute-value equation	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: absolute + value + equation. Study the complete expression as one field-specific unit.	an equation containing a variable inside absolute-value symbols	The absolute-value equation has solutions two units on either side of five.
428	compound inequality	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: compound + inequality. Study the complete expression as one field-specific unit.	two inequalities joined by and or or	The compound inequality describes all values between negative one and four.
429	interval notation	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: interval + notation. Study the complete expression as one field-specific unit.	a compact notation using brackets or parentheses to describe a set of real numbers	The solution x greater than three is written in interval notation with a parenthesis at three.
430	coordinate pair	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: coordinate + pair. Study the complete expression as one field-specific unit.	two values that locate a point in a plane	The coordinate pair negative two, five lies in the second quadrant.
431	direct proportion	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: direct + proportion. Study the complete expression as one field-specific unit.	a relationship in which two quantities have a constant ratio	Distance and time are in direct proportion when speed remains constant.
432	inverse proportion	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: inverse + proportion. Study the complete expression as one field-specific unit.	a relationship in which one quantity increases as the other decreases so their product stays constant	For a fixed trip, speed and travel time are in inverse proportion.
433	slope-intercept form	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: slope + intercept + form. Study the complete expression as one field-specific unit.	the linear-equation form y equals mx plus b	Slope-intercept form displays a line's slope and vertical intercept directly.
434	point-slope form	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: point + slope + form. Study the complete expression as one field-specific unit.	a linear-equation form using one point and the line's slope	Point-slope form makes it easy to write the equation from a point and a slope.
435	standard form	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: standard + form. Study the complete expression as one field-specific unit.	a conventional arrangement of a linear equation as Ax plus By equals C	The equation was rewritten in standard form with integer coefficients.
436	system of inequalities	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: system + of + inequalities. Study the complete expression as one field-specific unit.	two or more inequalities considered together	The solution to the system of inequalities is the overlapping shaded region.
437	linear inequality	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: linear + inequality. Study the complete expression as one field-specific unit.	an inequality whose boundary is a straight line	The linear inequality includes points above the dashed boundary.
438	exponential growth	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: exponential + growth. Study the complete expression as one field-specific unit.	increase by a constant percentage or factor over equal intervals	Compound interest produces exponential growth.
439	exponential decay	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: exponential + decay. Study the complete expression as one field-specific unit.	decrease by a constant percentage or factor over equal intervals	Radioactive material undergoes exponential decay.
440	percent change	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: percent + change. Study the complete expression as one field-specific unit.	change expressed as a percentage of the original value	The price rose from forty to fifty dollars, a percent change of twenty-five percent.
441	depreciation	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Suffix focus: -ation commonly forms a noun naming an action, process, or result.	decrease in an asset's value over time	The car's depreciation was steepest during its first year.
442	conditional probability	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: conditional + probability. Study the complete expression as one field-specific unit.	the probability of an event given that another event has occurred	The conditional probability of rain changes when dark clouds are already present.
443	permutation	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Suffix focus: -ation commonly forms a noun naming an action, process, or result.	an arrangement in which the order of chosen items matters	Each different ordering of the three books is a permutation.
444	combination	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Suffix focus: -ation commonly forms a noun naming an action, process, or result.	a selection in which order does not matter	Choosing three committee members from ten is a combination.
445	sample survey	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: sample + survey. Study the complete expression as one field-specific unit.	a study that asks questions of part of a population to estimate the whole population's views	The sample survey contacted randomly selected households.
446	observational study	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: observational + study. Study the complete expression as one field-specific unit.	research that records existing conditions without assigning treatments	The observational study compares sleep habits and grades without changing either.
447	controlled experiment	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: controlled + experiment. Study the complete expression as one field-specific unit.	a study that deliberately changes one factor while comparing outcomes under controlled conditions	The controlled experiment assigns plants to different light levels.
448	population parameter	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: population + parameter. Study the complete expression as one field-specific unit.	a numerical characteristic of an entire population	The true average height of all trees in the forest is a population parameter.
449	sample statistic	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: sample + statistic. Study the complete expression as one field-specific unit.	a numerical characteristic calculated from a sample	The sample mean is a sample statistic used to estimate the population average.
450	mean absolute deviation	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: mean + absolute + deviation. Study the complete expression as one field-specific unit.	the average distance of data values from their mean	A small mean absolute deviation indicates that values cluster near the mean.
451	population variance	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: population + variance. Study the complete expression as one field-specific unit.	the average squared distance of all population values from their mean	Population variance increases when observations spread farther from the average.
452	z-score	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: z + score. Study the complete expression as one field-specific unit.	the number of standard deviations a value lies above or below the mean	A z-score of two places the value two standard deviations above the mean.
453	normal distribution	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: normal + distribution. Study the complete expression as one field-specific unit.	a symmetrical bell-shaped probability distribution defined by its mean and standard deviation	Adult measurement data often approximate a normal distribution.
454	skewness	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Suffix focus: -ness forms a noun naming a quality or state.	the degree and direction of asymmetry in a data distribution	A few very high incomes create positive skewness.
455	correlation coefficient	noun Study Field: Grade 9 mathematics, computing, and data-literacy term Word study: Term structure: correlation + coefficient. Study the complete expression as one field-specific unit.	a number from negative one to one measuring the direction and strength of a linear relationship	A correlation coefficient near zero indicates little linear association.

Vocabulary reading and practice

Planning a Survey

Reading practice for pages 13–15. Five relevant words are highlighted.

English reading

A survey team plots each response as a coordinate pair and calculates a correlation coefficient to describe the linear association. A strong association does not prove direct proportion or causation. The team also uses conditional probability to compare subgroups, then considers every permutation of question order to test whether sequence changes responses.

Reading comprehension

1. What does the correlation coefficient describe?

It describes the linear association between variables.

2. Does a strong association prove causation?

No, a strong association does not prove causation.

3. Why test each permutation of question order?

The team wants to see whether order changes responses.

Vocabulary quiz

Complete 5 review questions for this page.

1. The ___ of rain changes when dark clouds are already present.

Answer: conditional probability

2. A ___ near zero indicates little linear association.

Answer: correlation coefficient

3. The ___ negative two, five lies in the second quadrant.

Answer: coordinate pair

4. Each different ordering of the three books is a ___.

Answer: permutation

5. Distance and time are in ___ when speed remains constant.

Answer: direct proportion

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9th Grade Vocabulary Words

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