baseline

Definitions

In interferometry, the distance between the farthest-separated points at which data is collected

A line which serves as the basis for measurement, calculation, or location. It is usually represented graphically as a horizontal line.
In displays, such as that of oscilloscopes and radars, the line which represents the reference level in the absence of other signals.
The average or reference signal level from which a pulse departs, and to which it returns.
In navigation, a line which joins two stations, such as the A and B stations within the loran radio navigation system.
acronymBL

(written as Baseline)
The starting point in a trial or cost-effectiveness analysis in which the data have not been influenced by the intervention being studied, or the routine, treatment etc. with which other treatments are to be compared.

noun the data used as a reference with which to compare future observations or results

noun an offensive manoeuvre carried out under fire, in which men or vehicles move forward into extended line in order to engage the enemy.

noun a boundary line at each end of a court that marks the limit of play in tennis, badminton or basketball
noun on a baseball field, a line running from home plate to first base and from home plate to third base, and extending into the outfield as foul lines
noun in baseball, the area within which a base runner must stay when running between bases