A set of adjacent points that has length but no width. A curve. A straight line is completely determined by two of its points, say A and B. The part of the line between any two of its points is a line segment.

A line drawn on a scatter graph to represent the best estimate of an underlying linear relationship between the variables.

In algebra, an adjective describing an expression, equation or relationship of degree one. Example: 2x + 3y = 7 is a linear equation. This linear equation with its two variables, x and y, can be represented as a straight line graph. The relationship between x and y is linear.

Symbol: l. A metric unit used for measuring volume or capacity. A litre is equivalent to 1000 cubic centimetres

The set of all points that satisfy given conditions. Example: in 3-D the locus of all points that are a given distance from a fixed point is a sphere. Plural: loci.

The common multiple of two or more numbers which has the lowest value. Example: 3 has the multiples 3, 6, 9, 12, 15, 18, 21, 24, etc. 4 has the multiples 4, 8, 12, 16, 20, 24... and 6 has the multiples 6, 12, 18, 24, 30... 

The common multiples of 3, 4 and 6 include 12, 24 and 36. So the lowest common multiple of 3, 4 and 6 is 12.