Meaning

noun a decrease in rate of change

noun the extent to which something is delayed or held back

noun any agent that retards or delays or hinders

originEtymology tree Proto-Italic *wre- Latin re- Latin tardus Latin retardō Proto-Indo-European *-tis Proto-Indo-European *-Hō Proto-Indo-European *-tiHō Proto-Italic *-tiō Latin -tiō Latin retardātiōlbor. English retardation Learned borrowing from Latin retardātiō.

Etymology from Wiktionary, CC BY-SA 3.0