Blackberry

wiktionary

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From Middle English blakberie, blakeberie(“ brambleberry”), from Old English blacu berġe, blæcberġe (attested in plural blaca berġan, equivalent to black +‎ berry.

etymonline

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blackberry (n.)

"fruit of the bramble," early 12c., from Old English blaceberian, from black (adj.) + berry. So called for the color. Also in Old English as bremelberie, bremelæppel (from bramble). The wireless handheld device of the same name was introduced 1999. Related: Blackberrying.