Meaning

noun a short stretch of railroad track used to store rolling stock or enable trains on the same line to pass

noun material applied to the outside of a building to make it weatherproof

verb take sides for or against; ; m siding against the current candidate"

originEtymology tree Proto-Indo-European *seh₁-der. Proto-Germanic *sīdaz Proto-Germanic *sīdǭ Old English sīde Middle English side English side English -ing English siding From side + -ing (“derivative noun, having the quality of”).

Etymology from Wiktionary, CC BY-SA 3.0