say it: sil
sill is a noun meaning "structural member consisting of a continuous horizontal timber forming the lowest member of a framework or supporting structure". It carries 2 recorded senses.
structural member consisting of a continuous horizontal timber forming the lowest member of a framework or supporting structure
(geology) a flat (usually horizontal) mass of igneous rock between two layers of older sedimentary rock
geology
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for sill come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.