Word Origin & History
O.E. gretan "to come in contact with" (in sense of "attack, accost" as well as "salute, welcome"), from W.Gmc. *grotja (cf. O.S. grotian, O.Fris. greta, Du. groeten, O.H.G. gruozen, Ger. grußen "to salute, greet"), perhaps originally "to resound" (via notion of "cause to speak"), causative of P.Gmc.
*grætanan, root of O.E. grætan (Anglian gretan) "weep, bewail," and greet still means "cry, weep" in Scot. & northern England dialect. Grætan is probably also the source of the second element in regret. First record of greeting card is from 1898.