minor arc
Technical geometry term for the shorter of the two arcs connecting two points on a circle. The opposite is 優弧 (ゆうこ, major arc).
Find the length of the minor arc connecting two points on the circumference.
Compound of 劣 (れつ, inferior, lesser) and 弧 (こ, arc), literally 'lesser arc'. The reading れっこ results from assimilation of れつこ.