ASVAB key terms

The process by which green plants use sunlight, water, and carbon dioxide to make sugar and release oxygen. Chlorophyll in the leaves captures the light energy that drives the reaction.

The energy an object has because it is moving. It increases with both mass and speed, so a heavier or faster object carries more of it.

The smallest unit of an element that still has that element's properties. It consists of a nucleus of protons and neutrons surrounded by electrons.

A scale from 0 to 14 that describes how acidic or basic a solution is. Below 7 is acidic, 7 is neutral, and above 7 is basic.

All the living things in an area plus the nonliving surroundings they interact with, such as soil, water, and climate. Energy and nutrients cycle among these parts.

A way of expressing a number as a part of 100. For example, 25 percent means 25 out of every 100, or one quarter of the whole.

A comparison of two quantities by division, often written as a fraction or with a colon. It tells how much of one thing there is for each unit of another.

The arithmetic average: add all the values in a set and divide by how many values there are. It is one way to describe the center of a data set.

A ratio that compares two quantities with different units, such as miles per hour or dollars per pound. It tells how one quantity changes relative to another.

Changing a measurement from one unit to another without changing its value, usually by multiplying by a fraction equal to one, such as 12 inches over 1 foot.

An equation stating that two ratios are equal. Solving one usually means finding a missing value in a comparison, such as 3/4 = x/12.

A word that means the same as, or nearly the same as, another word. For example, 'big' and 'large' are synonyms.

A word that means the opposite of another word. For example, 'hot' is an antonym of 'cold,' and 'expand' is an antonym of 'shrink.'

A word part attached to the front of a root or base word that changes its meaning, such as 'un-' in 'unfair' or 'pre-' in 'preview.'

Information in the words and sentences around an unfamiliar word that helps you figure out its meaning, such as a definition, example, contrast, or cause-and-effect relationship.

The feelings or associations a word suggests beyond its dictionary meaning. 'Cheap' and 'inexpensive' have similar meanings but very different connotations.

The central point a paragraph or passage is trying to make. Other sentences usually support or explain it, and it is often stated in a topic sentence.

A conclusion you reach by combining details in a passage with what you already know. It is not stated directly but is strongly suggested by the text.

A fact, example, statistic, or reason that backs up the main idea of a passage. Details answer questions like who, what, when, where, or why.

The writer's attitude toward the subject, revealed through word choice and details. It might be serious, humorous, sarcastic, objective, or critical.

A letter or symbol that stands for an unknown or changing number in an expression or equation, such as x in 3x + 5 = 20.

A small number written above and to the right of a base that tells how many times the base is multiplied by itself. In 2 to the third power, the exponent 3 means 2 x 2 x 2.

A whole number greater than 1 whose only positive factors are 1 and itself. Examples include 2, 3, 5, 7, and 11; the number 1 is not prime.

The agreed sequence for evaluating an expression: parentheses first, then exponents, then multiplication and division left to right, then addition and subtraction left to right.

A measure of how steep a line is, found by dividing the vertical change by the horizontal change between two points. It describes the line's rate of change.

The amount of surface a flat shape covers, measured in square units such as square inches or square meters. Formulas differ by shape, such as length times width for a rectangle.

The electrical pressure that pushes charges through a circuit, measured in volts. A higher voltage can push more current through the same amount of resistance.

The flow of electric charge through a conductor, measured in amperes. It is the rate at which charge moves past a point in a circuit.

The opposition to the flow of electric current in a material, measured in ohms. More resistance means less current for a given voltage.

The relationship stating that voltage equals current times resistance. If you know any two of these three values, you can calculate the third.

A circuit in which components are connected end to end so the same current flows through each one. If one part breaks, the whole circuit stops working.

A material that lets electric charge flow through it easily, usually because it has loosely held electrons. Copper and aluminum are common examples.

A twisting force that tends to rotate an object, calculated as force times the distance from the pivot. Mechanics measure it in pound-feet or newton-meters.

The comparison of the number of teeth on a driving gear to the number on a driven gear. It determines the changes in speed and turning force.

The sequence an internal combustion engine repeats: intake, compression, power, and exhaust. The piston moves down and up twice to complete one full cycle.

A precision measuring tool with a calibrated screw used to measure small thicknesses or diameters, often to the nearest thousandth of an inch or hundredth of a millimeter.

The number of times a machine multiplies the force you apply. It equals the output force divided by the input force, or effort distance divided by resistance distance.

Force applied over a given area, measured in units such as pounds per square inch. The same force creates more pressure when concentrated on a smaller area.

A force that resists motion when two surfaces touch and slide or try to slide past each other. It converts some of the motion into heat.

A rigid bar that pivots on a fixed point called a fulcrum. Levers multiply force or increase speed depending on where the load and effort are placed.