Ben
late 18th century: from Scottish Gaelic and Irish beann .
wiktionary
From Middle English ben, bene, from Old English bēn(“prayer, request, favor, compulsory service”), from Proto-Germanic *bōniz(“supplication”), from Proto-Indo-European *bʰeh₂-(“to say”). Related to ban. More at boon.
From Middle English ben, bene, variation of bin, binne(“within”), from Old English binnan(“within, in, inside of, into”), equivalent to be- + in.
From Middle English been, from Old French and Medieval Latin, probably from a North African pronunciation of Arabic بَان (bān, “ben tree”)
From Arabic بِن (bin) and Hebrew בן (ben, “son”).
Borrowed from Scots ben, benn, from Scottish Gaelic beinn
UK C16. Probably from Latin bene or Italian bene.
Shortening.
etymonline
ben (n.)
"mountain peak" in Celtic place names (especially of roughly pyramidal peaks standing alone), 1788, from Gaelic beinn "peak, summit, mountain," from Old Irish *benno- "peak, horn, conical point," from PIE *bend- "projecting point."