- reef (n.1)
- "rock ridge underwater," 1580s, riffe, probably via Dutch riffe, from a Scandinavian source such as Old Norse rif "ridge in the sea; reef in a sail," literally "rib" (see rib (n.)).
- reef (n.2)
- "horizontal section of sail," late 14c. (mid-14c. in rif-rope), from a Scandinavian source such as Old Norse rif "reef of a sail," probably a transferred use of rif "ridge under the sea; rib" (see rib (n.) and compare reef (n.1)). German reff, Swedish ref, Norwegian riv, Danish reb likely all are from the Old Norse word.
- reef (v.)
- 1660s, "take in, roll up" (as one would a section of a sail on a ship), from reef (n.2). Related: Reefed; reefing.
