surcingle (n.)

word-forming element meaning "over, above, beyond, in addition," especially in words from Anglo-French and Old French, from Old French sour-, sor-, sur-, from Latin super "above, over," from PIE root *uper "over."

1859, American English, "saddle-girth," from Spanish cincha "girdle," from Latin cingulum "a girdle, a swordbelt," from cingere "to surround, encircle," from PIE root *kenk- (1) "to gird, encircle" (source also of Sanskrit kankate "binds," kanci "girdle;" Lithuanian  kinkau, kinkyti "to harness horses"). Replaced earlier surcingle. Sense of "an easy thing" is 1895 (in lead-pipe cinch), via notion of "a firm or sure hold" (1888).