ARBORETUM Meaning of ARBORETUM in English [ ˌα:bə'ri:təm ]■ noun ( plural ~s or arboreta -tə ) a botanical garden devoted to trees.OriginC19: from L., 'a place with trees', from arbor 'tree'. Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004