ROCN key terms

A word that has the same or nearly the same meaning as another word, such as 'rapid' and 'swift', used to test whether two statements express equivalent ideas.

A word whose meaning is opposite to another word, such as 'expand' and 'contract'. Verbal reasoning items often ask you to pick the answer most nearly opposite in meaning.

A comparison stating that two pairs of words share the same relationship, as in 'sailor is to ship as pilot is to aircraft'. The task is to identify the underlying relationship.

A conclusion drawn from stated evidence rather than stated outright. A valid inference must follow necessarily from the passage, not merely seem plausible or personally agreeable.

An unstated idea that a argument depends on for its conclusion to hold. If the assumption is false, the reasoning collapses, which is why test items ask you to identify it.

The claim an argument tries to establish, supported by the other statements called premises. Distinguishing the conclusion from supporting evidence is the core skill in argument analysis.

A stated reason or piece of evidence offered in support of an argument's conclusion. Premises are what the arguer asserts as true; they are not what is being proven.

A comparison of two quantities by division, showing how many times one value contains another. A ratio of 3 to 4 means the first quantity is three quarters of the second.

An equation stating that two ratios are equal, such as 3/4 = 9/12. Solving a proportion means finding the unknown value that keeps both sides balanced.

A fraction expressed out of one hundred, so 45 percent means 45 per 100, or 0.45. Percentage problems often require converting between fractions, decimals, and rates.

The sum of a set of values divided by the number of values. To find a missing value given the mean, multiply the mean by the count and subtract the known values.

The middle value of a data set arranged in order. With an even number of values, the median is the mean of the two central values, which resists distortion by outliers.

A ratio comparing quantities with different units, such as knots per hour or liters per minute. Rate problems usually use the relationship distance equals rate multiplied by time.

Changing a measurement from one unit to another while preserving the true quantity, by multiplying by a conversion factor equal to one, such as 1 nautical mile equals 1.852 kilometers.

The fixed relationship between a drawing or chart and the real object it represents, often written as a ratio such as 1 to 50,000. Scale lets you compute real distances from measured ones.

A rigid bar pivoting on a fulcrum, used to multiply force or distance. The effort times its distance from the fulcrum equals the load times its distance when balanced.

The fixed pivot point on which a lever turns. Moving the fulcrum closer to the load increases the force the lever can lift but reduces the distance moved.

The factor by which a machine multiplies an applied force, calculated as output force divided by input force. A value above one means the machine reduces the effort needed.

A wheel with a grooved rim carrying a rope or belt, used to change the direction of a force or, in block-and-tackle systems, to reduce the effort needed to lift a load.

A toothed wheel that meshes with another to transmit motion and torque. A smaller driving gear turns a larger driven gear more slowly but with greater turning force.

Force applied over a given area, commonly measured in pascals or pounds per square inch. The same force produces greater pressure when concentrated on a smaller area.

The use of confined liquid, which is nearly incompressible, to transmit force. Pressure applied at one point is transmitted throughout the fluid, multiplying force over a larger piston.

A turn of a figure or object about a fixed point or axis, described by an angle and a direction such as 90 degrees clockwise. The shape keeps its size and proportions.

A mirror-image flip of a figure across a line, producing a reversed but congruent shape. Left-right orientation changes while distances and angles are preserved.

A slide of a figure in a straight line without turning or flipping it. The shape keeps the same orientation and size, only its position changes.

A direction expressed as an angle measured clockwise from north, given as three digits such as 045 degrees. Bearings allow precise description of heading or relative position.

A flat pattern that folds into a three-dimensional solid, such as six squares forming a cube. Spatial items ask which net correctly assembles into a given shape.

The upward force a fluid exerts on an object placed in it, equal to the weight of the fluid displaced. An object floats when this force matches its own weight.

Mass per unit volume of a substance, often expressed in grams per cubic centimeter. An object denser than the fluid around it sinks; a less dense object rises or floats.

A rapid chemical reaction in which a fuel reacts with oxygen, releasing heat and light. Complete combustion of hydrocarbons yields carbon dioxide and water vapor.

The process by which green plants use sunlight, water, and carbon dioxide to make glucose and release oxygen. It is the base of most food chains and removes carbon dioxide from air.

A community of living organisms interacting with each other and with their nonliving environment, such as water, soil, and climate. Energy enters mostly as sunlight and flows through feeding levels.

The central point a passage is written to convey, broad enough to cover all its supporting details. Test items ask you to choose the statement that best captures it.

A fact, example, or reason in a passage that backs up or explains the main idea. Details answer questions about who, what, when, where, or how much.

The writer's attitude toward the subject, revealed through word choice, such as critical, neutral, or admiring. Tone differs from mood, which is the feeling created in the reader.

A unit of speed equal to one nautical mile per hour, roughly 1.852 kilometers per hour. Vessel speed and wind speed at sea are normally reported in knots.

The direction in which a vessel's bow points at a given moment, usually expressed in degrees from north. Heading differs from course when wind or current pushes the vessel sideways.

The left and right sides of a vessel when facing forward, respectively. Port is conventionally lit red and starboard green, which helps identify another vessel's aspect at night.

The formal line of authority from senior to junior levels through which orders pass and accountability flows. Members normally report concerns through this line rather than around it.

The number of subordinates a leader can effectively supervise. A wide span suits simple, routine work; a narrow span suits complex or high-risk tasks needing close direction.

Assigning a task and the authority to complete it to a subordinate while retaining overall accountability for the outcome. Effective delegation includes clear standards and a deadline.

The active role of subordinates in supporting a leader, including taking initiative, giving honest feedback, and carrying out orders competently. Good followership is a skill, not passive obedience.