Shelf
Middle English: from Middle Low German schelf ; related to Old English scylfe ‘partition’, scylf ‘crag’.
wiktionary
From Middle English schelfe, probably from Old English sċylfe(“deck of a ship”), distantly related to sculpt, carve and shell. Cognate to Dutch schelf.
etymonline
shelf (n.)
late 14c., from Middle Low German schelf "shelf, set of shelves," or from Old English cognate scylfe, which perhaps meant "shelf, ledge, floor," and scylf "peak, pinnacle," from Proto-Germanic *skelf- "split," possibly from the notion of a split piece of wood (compare Old Norse skjölf "bench"), from PIE root *skel- (1) "to cut."
Shelf life first recorded 1927. Phrase on the shelf "out of the way, inactive" is attested from 1570s; of unmarried women with no prospects from 1839. Off the shelf "ready-made" is from 1936. Meaning "ledge of rock" is from 1809, perhaps from or influenced by shelf (n.2). Related: Shelves.
shelf (n.2)
"sandbank," 1540s, of unknown origin. Related: Shelfy "abounding in sandbanks."