1. (Science: anatomy) The space from the thumb to the end of the little finger when extended; nine inches; eighth of a fathom.
2. Hence, a small space or a brief portion of time. Yet not to earth's contracted span thy goodness let me bound. (pope) Life's but a span; I'll every inch enjoy. (Farquhar)
3. The spread or extent of an arch between its abutments, or of a beam, girder, truss, roof, bridge, or the like, between its supports.
4. A rope having its ends made fast so that a purchase can be hooked to the bight; also, a rope made fast in the center so that both ends can be used.
5. A pair of horses or other animals driven together; usually, such a pair of horses when similar in colour, form, and action. Span blocks, a large bolt driven through the forecastle deck, with a triangular shackle in the head to receive the heel of the old-fashioned fish davit.
Origin: AS. Spann; akin to D. Span, OHG. Spanna, G. Spanne, Icel. Sponn. See Span.