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).
円周上の二点を結ぶ劣弧の長さを求めよ。
Find the length of the minor arc connecting two points on the circumference.
優弧 is the larger arc formed by two points on a circle, while 劣弧 is the smaller, complementary arc.
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.