late 14c., "having corners," past-participle adjective from corner (v.). Figurative sense "forced or driven into a position where surrender or defeat is inevitable" is from 1824.
1540s, "to exist;" c. 1600, "retain the existing state," from French subsister and directly from Latin subsistere "to stand still or firm, take a stand, take position; abide, hold out," from sub "under, up to" (see sub-) + sistere "to assume a standing position, stand still, remain; set, place, cause to stand still" (from PIE *si-st-, reduplicated form of root *sta- "to stand, make or be firm"). Meaning "to support oneself" (in a certain way) is from 1640s. Related: Subsisted; subsisting.