- sill
- Old English syll "beam, large timber serving as a foundation of a wall," from Proto-Germanic *suljo (cf. Old Norse svill "framework of a building," Middle Low German sull, Old High German swelli, German Schwelle "sill"), perhaps from PIE root *swel- "post, board" (cf. Greek selma "beam"). Meaning "lower horizontal part of a window opening" is recorded from early 15c.