late 14c., posteriorite, "condition of occurring later in time, state of being subsequent," from Old French posteriorite (Modern French postériorité), from Medieval Latin posterioritatem (nominative posterioritas), from Latin posterior "later" (see posterior (adj.)).
postdate
postdiluvial
posted
poster
posterior
posteriority
posterity
postern
post-glacial
post-graduate
post-haste