Naut. [f. JACK sb.3 + STAFF.]
1. A short staff, usually set upon the bowsprit or at the bow of a ship, on which the flag called the jack (JACK sb.3) is hoisted.
1692. Capt. Smith’s Seaman’s Gram., I. xiv. 65. Jack staff and Jack.
1794. Rigging & Seamanship, I. 175. The Jack-staff is a short staff erected on the aftside of the bowsprit-cap, to expand the jack.
1880. Preble, Hist. of Flag (ed. 2), v. 509. The stars and stripes for the stern, the boat-flag for the jackstaff, and two blue flags for the wheel-houses.
2. Used (? erron.) for JACOB’S STAFF (sense 2 a).
1891. J. Winsor, Columbus, xi. 261. Whether the cross-staff or Jackstaff, a seaboard implement somewhat more convenient than the astrolabe, was known to Columbus is not very clear.
