Other forms: sills
A sill is the little shelf at the bottom of a window where plants sit. A window sill, on the sill, a stone sill.
Its real job is to throw rainwater clear of the wall below, which is why an external one slopes and has a groove underneath. The inside ledge is the part people use. In geology, a sill is a sheet of igneous rock forced between layers. Note that the Old English word meant a threshold or foundation beam.
1nounsillThe ledge at the bottom of a window.
“The cat sat on the sill all morning, watching the birds outside.”
2nounsheetA sheet of rock forced between layers.
“The dark band in the cliff is a sill of volcanic rock that pushed into the older sandstone.”
sill is a ledge.
Also accepted in games: windowsill
Old English syll meant a threshold or foundation beam, from a Germanic root about beams. The window sense is a narrowing.
Middle English
sille
English, today
sill
Built from
From Middle English sille. From Middle English sille, selle, sulle, from Old English syll, syl (“sill, threshold, foundation, base, basis”), from Proto-Germanic sulī (“bar, sill”), from Proto-Indo-European sel-, swel- (“beam, board, frame, threshold”). Cognate with Scots sil, sill (“balk, beam, floor, sill”), Dutch zulle (“sill”), Low German Sull, Sülle (“threshold, ramp, sill”), German Süll, Sülle (“threshold, sill”), Danish syld (“base of a framework building”), Swedish syll (“joist, cross-tie”), Norwegian syll, Icelandic syll, sylla (“sill”). Related also to German Schwelle (> Danish svelle), Old Norse svill, Latin silva (“wood, forest”), Ancient Greek ὕλη.
Etymology from Wiktionary, CC BY-SA