horizontal+line
131base line — [bās′līn΄] 1. a) a line serving as a base b) any starting or reference point, figure, amount, level, etc. with which others can be measured or compared c) Surveying a horizontal line measured with special accuracy to provide a base for survey by… …
132base line — [bās′līn΄] 1. a) a line serving as a base b) any starting or reference point, figure, amount, level, etc. with which others can be measured or compared c) Surveying a horizontal line measured with special accuracy to provide a base for survey by… …