sills

(noun) United States operatic soprano (born in 1929). Synonyms: Sills, Beverly Sills, Belle Miriam Silverman.

(noun) structural member consisting of a continuous horizontal timber forming the lowest member of a framework or supporting structure. Synonyms: sill.

(noun) (geology) a flat (usually horizontal) mass of igneous rock between two layers of older sedimentary rock. Synonyms: sill.