"short, thick stick of wood used for fuel," mid-15c., from Old French billette, diminutive of bille "stick of wood," from Medieval Latin billia "tree, trunk," which is possibly from Gaulish (compare Irish bile "tree trunk").
"fruit of the wild apple tree," a small and tart variety of apple, c. 1300 (mid-13c. in place-names), crabbe, perhaps from Scandinavian words (compare Swedish krabbäpple) which are of obscure origin. As "walking stick made of crab wood" by 1740. Crab-tree is from early 15c. Crab-apple for "fruit of the wild apple tree" is by 1712.
shrub much cultivated for its profuse, handsome flowers, also noted for its leathery evergreen leaves, 1660s, from French rhododendron and directly from Latin rhododendron, from Greek rhododendron, etymologically "rose-tree," from rhodon "rose" (see rose (n.1)) + dendron "tree" (from PIE *der-drew-, from root *deru- "to be firm, solid, steadfast," also forming words for "wood, tree").