Emily Dickinson Lexicon

SPUR, n. [Sax. spur; D. spoor; G. sporn; Dan. spore; Ir. spor; W. yspardun; Fr. eperon; It. sprone; coinciding in elements with spear. Class Br.]

1. An instrument having a rowel or little wheel with sharp points, worn on horsemen's heels, to prick the horses for hastening their pace. Girt with rusty sword and spur. – Hudibras. Hence, to set spurs to a horse, is to prick him and put him upon a run.
2. Incitement; instigation. The love of glory is the spur to heroic deeds.
3. The largest or principal root of a tree; hence perhaps, the short wooden buttress of a post; [that is, in both cases, a shoot.]
4. The hard pointed projection on a cock's leg, which server as an instrument of defense and annoyance. – Ray.
5. Something that projects; a snag. – Shak.
6. In America, a mountain that shoots from any other mountain or range of mountains, and extends to some distance in a lateral direction, or at right angles.
7. That which excites. We say, upon the spur of the occasion; that is, the circumstances or emergency which calls for immediate action.
8. A sea swallow. – Ray.
9. The hinder part of the nectary in certain flowers, shaped like a cock's spur. – Martyn.
10. A fungus [Spermœdia Clavus,] growing within the glumes of rye, wheat, couch-grass, herd's-grass, lie. [Fr. ergot.]
11. In old fortifications, a wall that crosses a part of the rampart and joins to the town wall.