"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.
mid-15c., from Latin ingressus "an advance; walking; an entry," from ingress-, past participle stem of ingredi "to step into, enter," from in- "in" (from PIE root *en "in") + gradi "to step, go" (from PIE root *ghredh- "to walk, go"). The verb meaning "to enter, go in" sometimes said to be American English, but it is attested from early 14c.
"prologue, preface, preliminary statement," late 14c., from Old French preambule (13c.) and directly from Medieval Latin preambulum, neuter adjective used as a noun, properly "preliminary," from Late Latin praeambulus "walking before," from Latin prae "before" (see pre-) + ambulare "to walk" (see amble (v.)). Especially the introductory paragraph of a statute or resolution, stating the reason for and intent of what follows. Related: Preambulary.
c. 1300, "metal bar bent at the ends for fastening," from Old French crampoun "cramp, brace, staple" (13c.), from Germanic (see cramp (n.1); also compare cramp (n.2)). As "apparatus used in the raising of heavy weights," mid-15c. By 1789 as "plate set with spikes, fastened to the foot to assist in walking on ice or climbing rock."