erection (n.)

mid-15c., "establishment; advancement," from Late Latin erectionem (nominative erectio), noun of action from past participle stem of erigere "to set up, erect" (see erect (adj.)). Meanings "the putting up" (of a building, etc.), "stiffening of the penis" (also sometimes of the turgidity and rigidity of the clitoris) are both from 1590s.