Home › Words › U › undersillundersillundersill means beneath a sill.EtymologyFrom under- + sill.adjBeneath a sill.e.g.“A vinyl undersill trim or finish trim should be used under windowsills to receive the cut edges of the siding.” — 1975, Robert Scharff, The complete book of home remodeling, page 292:nounA sill placed underneath something.Definitions & examples from Wiktionary (CC BY-SA 3.0).Words closest in meaningBy meaning, not spelling — each word's AI semantic fingerprint, nearest first.silled 71% match — Furnished with a sill. vs undersill →mudsill 66% match — The lowest sill of a structure, usually placed in or on the ground. vs undersill →undersnow 58% match — Beneath snow. vs undersill →windowsill 58% match — The horizontal member protruding from the base of a window frame. vs undersill →subfenestral 57% match — Beneath a window. vs undersill →undervine 57% match — Beneath a vine vs undersill →underneath 57% match — Below; in a place beneath. vs undersill →undercabinet 57% match — Beneath a cabinet. vs undersill →