I. adjective suffix
Etymology: Middle English -som, from Old English -sum; akin to Old High German -sam -some, Old English sum some
characterized by a (specified) thing, quality, state, or action <awesome> <burdensome> <cuddlesome> II. noun suffix Etymology: Middle English (northern dialect) -sum, from Middle English sum, pronoun, one, some group of (so many) members and especially persons <foursome> III. noun combining form Etymology: New Latin -somat-, -soma, from Greek sōmat-, sōma 1. body <chromosome> 2. chromosome <monosome>
New Collegiate Dictionary. 2001.