Sill word meaning and definition

[noun] structural member consisting of a continuous horizontal timber forming the lowest member of a framework or supporting structure
[noun] (geology) a flat (usually horizontal) mass of igneous rock between two layers of older sedimentary rock

\Sill\, n. [OE. sille, sylle, AS. syl, syll; akin to G. schwelle, OHG. swelli, Icel. syll, svill, Sw. syll, Dan. syld, Goth. gasuljan to lay a foundation, to found.] The basis or foundation of a thing; especially, a horizontal piece, as a timber, which forms the lower member of a frame, or supports a structure; as, the sills of a house, of a bridge, of a loom, and the like. Hence:
(a) The timber or stone at the foot of a door; the threshold.
(b) The timber or stone on which a window frame stands; or, the lowest piece in a window frame.
(c) The floor of a gallery or passage in a mine.
(d) A piece of timber across the bottom of a canal lock for the gates to shut against. {Sill course} (Arch.), a horizontal course of stone, terra cotta, or the like, built into a wall at the level of one or more window sills, these sills often forming part of it.
\Sill\, n. [Cf. {Thill}.] The shaft or thill of a carriage. [Prov. Eng.]
\Sill\, n. [Cf. 4th {Sile}.] A young herring. [Eng.]

Morse code: ... .. .-.. .-..