ETYM Latin dimensio, from dimensus, p. p. of dimetiri to measure out; di- = dis- + metiri to measure: cf. French dimension. Related to Measure.
1. A measure of the size of something in a particular direction, esp. length or width or height.
2. One of three coordinates that determine a position in space.
In science, any directly measurable physical quantity such as mass (M), length (L), and time (T), and the derived units obtainable by multiplication or division from such quantities.
For example, acceleration (the rate of change of velocity) has dimensions (LT-2), and is expressed in such units as km s-2. A quantity that is a ratio, such as relative density or humidity, is dimensionless.
In geometry, the dimensions of a figure are the number of measures needed to specify its size. A point is considered to have zero dimension, a line to have one dimension, a plane figure to have two, and a solid body to have three.
ETYM French, from Latin proportio; pro before + portio part or share. Related to Portion.
1. Harmonious arrangement or relation of parts or elements within a whole (as in a design); SYN. balance.
2. Magnitude or extent; SYN. dimension.
3. The quotient obtained when the magnitude of a part is divided by the magnitude of the whole; SYN. proportionality.
The relation of a part to the whole (usually expressed as a fraction or percentage). In mathematics two variable quantities x and y are proportional if, for all values of x, y = kx, where k is a constant. This means that if x increases, y increases in a linear fashion.
A graph of x against y would be a straight line passing through the origin (the point x = 0, y = 0). y is inversely proportional to x if the graph of y against 1/x is a straight line through the origin. The corresponding equation is y = k/x. Many laws of science relate quantities that are proportional (for example, Boyle’s law).