be·side (bĭ-sīdʹ)prep. 1. At the side of; next to. 2. a. In comparison with: a proposal that seems quite reasonable beside the others. b. On an equal footing with: has earned a place beside the best performers in the business. 3. In addition to: “Many creatures beside man live in communities” (Stuart Chase). See Usage Note at besides. 4. Except for. See Usage Note at besides. 5. Not relevant to: a remark that was beside the point.adv. Archaic 1. In addition. 2. Nearby.Idiom:beside (oneself) In a state of extreme excitement or agitation: They were beside themselves with glee. [Middle English biside, from Old English be sīdan: be, by; see by1 + sīde, side.]