- base line
- noun
: a main line taken as or representing a base: asa. : base 6b; specifically : a line extending east and west from a chosen reference point on a principal meridian and forming with the meridian a pair of coordinate axes for locating township and section corners — used in United States public-land surveyingb. : the line joining the base piece and the base point in artillery firec. : the lowest horizontal line in a profile drawing of a ship used as a base for vertical measurementsd. of a perspective drawing : the line formed by the intersection of the ground plane and the picture planee. : the area within which a baseball player must keep when running between basesg. : the lower horizontal guideline for aligning capitals in freehand letteringh. : a known quantity used as a control for further experimentation
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base line, or base|line «BAYS LYN», noun.1. a line used as a base, from which operations are carried on, or on which they depend or rest.2. a) Baseball. the unmarked lane or path between one base and the next. A player must keep to it while remaining between bases. b) Tennis. the line at either end of the court parallel to the net: »He began to net his returns and overdrive the base line (Time).
3. Surveying. any precisely determined line forming a side of a triangle, so that when the adjacent angles are measured, the relative position of the third vertex is determined.
Useful english dictionary. 2012.