Is 'glen' English, or is it actually Gaelic?

'Glen' is a word borrowed from Gaelic 'glen'. The word entered the English language some time around the 15th century.

glen [noun] [15th century]

A secluded narrow valley

See 'glen' on the Loan Words Map

See more loan words from Gaelic.

Etymology: Middle English (Scots), valley, from Scottish Gaelic & Irish 'gleann' from Old Irish 'glenn'

See more loan words from 1400s.