From Proto-Italic *rēti-, of uncertain origin. Some theories:
* From Proto-Indo-European *h₁reh₁- (“separate, loose”), related to rārus, Lithuanian rėtis (“sieve”).
* Alternatively, borrowed from Semitic; compare Hebrew רֶשֶׁת (rešet, “net (for fishing and bird-catching)”), Ugaritic 𐎗𐎘𐎚 (rṯt, “net”).