[oak] n, pl oaks or oak often attrib [ME ook, fr. OE ac; akin to OHG eih oak and perh. to Gk aigilops, a kind of oak] (bef. 12c) 1 a: any of a genus (Quercus) of trees or shrubs of the beech family that produce acorns; also: any of various plants related to or resembling the oaks b: the tough hard durable wood of an oak tree
2: the leaves of an oak used as decoration -- oak.en adj