adj. 1 having much wealth. 2 (often foll. by in, with) splendid, costly, elaborate (rich tapestries; rich with lace). 3 valuable (rich offerings). 4 copious, abundant, ample (a rich harvest; a rich supply of ideas). 5 (often foll. by in, with) (of soil or a region etc.) abounding in natural resources or means of production; fertile (rich in nutrients; rich with vines). 6 (of food or diet) containing much fat or spice etc. 7 (of the mixture in an internal-combustion engine) containing a high proportion of fuel. 8 (of colour or sound or smell) mellow and deep, strong and full. 9 a (of an incident or assertion etc.) highly amusing or ludicrous; outrageous. b (of humour) earthy. richen v.intr. & tr. richness n.
[ OE rice f. Gmc f. Celt., rel. to L rex king: reinforced in ME f. OF riche rich, powerful, of Gmc orig. ]