ACT Aspire Grade 9 key terms

The grammar rule that a verb must match its subject in number and person, so a singular subject takes a singular verb and a plural subject takes a plural verb.

The rule that a pronoun must match the noun it refers to in number and gender, so a singular noun takes a singular pronoun and a plural noun takes a plural pronoun.

An error in which two independent clauses are joined only by a comma, with no coordinating conjunction or other punctuation to show the boundary between them.

Two or more independent clauses written together without correct punctuation or a conjunction, creating a confusing sentence that needs a period, semicolon, or joining word.

A punctuation mark used mainly to join two closely related independent clauses, or to separate items in a list when the items themselves contain commas.

A phrase that describes something not clearly stated in the sentence, often because the noun it should modify is missing or placed too far away.

Using the same grammatical form for items in a list or for ideas that are compared, which makes writing clearer and easier to follow.

A word such as however or therefore that connects ideas across sentences or clauses; it shows a logical relationship but is not a true conjunction.

A group of words with a subject and verb that cannot stand alone as a sentence because it begins with a word such as because, although, or when.

An equation whose graph is a straight line, typically written in forms such as y = mx + b, where each variable has an exponent of one.

A measure of how steep a line is, calculated as the change in y divided by the change in x between two points on the line.

A relationship in which each input value is paired with exactly one output value, often shown as a rule, table, graph, or equation.

Two or more equations that share variables and are solved together to find values that make all the equations true at the same time.

A shortcut for combining powers, such as adding exponents when multiplying like bases or subtracting them when dividing like bases, while keeping the base unchanged.

A way to write very large or very small numbers as a number between 1 and 10 multiplied by a power of 10.

The rule that in a right triangle, the square of the hypotenuse equals the sum of the squares of the other two sides: a² + b² = c².

The middle value in a data set ordered from least to greatest; if there are two middle values, it is their average.

A mathematical statement comparing two expressions that are not necessarily equal, using symbols such as <, >, ≤, or ≥ to show their relationship.

The ratio that compares a measurement in a drawing or model to the corresponding measurement in the actual object, used to enlarge or reduce figures.

The central point a passage conveys about its topic, often stated in a topic sentence or implied through details and examples.

A conclusion drawn by combining details in a text with a reader's background knowledge, even though the text does not state the conclusion directly.

The reason an author writes a text, such as to inform, persuade, entertain, or explain, which shapes the content and style.

The attitude a writer expresses toward the subject or audience, conveyed through word choice, sentence structure, and details, and it can be serious, humorous, or critical.

The way ideas in a passage are organized, such as chronological order, cause and effect, comparison, or problem and solution.

Information in nearby words or sentences that helps a reader figure out the meaning of an unfamiliar word without using a dictionary.

Language that goes beyond literal meaning, using devices such as simile, metaphor, and personification to create vivid comparisons or effects.

A testable prediction or proposed explanation that can be supported or rejected by evidence collected in an investigation before the main experiment.

The factor that an investigator deliberately changes in an experiment so that its effect on another factor can be observed and measured.

The factor that is measured or observed in an experiment; it may change in response to the independent variable and provides the results.

The comparison group in an experiment that does not receive the treatment being tested, helping show whether the treatment caused an effect.

How close repeated measurements are to one another, regardless of whether they are close to the true value; a precise set may still be inaccurate.

A fact gathered directly through the senses or with instruments, such as a measurement or a description of what happened.

A sentence that states the main claim of an essay and previews the reasoning or evidence the writer will use to support it.

A sentence, usually at the start of a paragraph, that introduces the paragraph's main idea and connects it to the larger argument.

An opposing viewpoint that a writer acknowledges and answers in order to show awareness of other positions and strengthen the argument.

The quality of writing that makes sentences and paragraphs flow smoothly, achieved through transitions, repeated key terms, and logical order.

A brief plan that lists an essay's main points and supporting details in the order they will appear before drafting.

The stage of writing in which a writer reconsiders and improves ideas, organization, and word choice, rather than only fixing spelling and grammar.