the.com/lemon tree

means A citrus tree (Citrus limon) grown for its fragrant blossoms, evergreen foliage, and tart yellow fruit.

from Lemon traveled a long road into English, borrowed through French 'limon' and Italian 'limone' from Arabic 'laymūn,' which in turn likely traces back to Persian 'līmūn' — a word used broadly for citrus fruits. The 'tree' part is just plain Old English, tacked on once the fruit's name settled into the language. The genus name Citrus is Latin, originally used for citron. So the lemon tree's name, like the fruit itself, is an import — shipped west along trade routes long before the plant itself took root in Europe.