Noah Webster's New International Dictionary of the English Language

1. (p. pr.& vb. n.) of Side.

2. (n.) Attaching one's self to a party.

3. (n.) A side track, as a railroad; a turnout.

4. (n.) The covering of the outside wall of a frame house, whether made of weatherboards, vertical boarding with cleats, shingles, or the like.

5. (n.) The thickness of a rib or timber, measured, at right angles with its side, across the curved edge; as, a timber having a siding of ten inches.