"horizontal bar serving as a support for various purposes," late 14c., "rod, pole, perch for a hawk," a variant of perch (n.1) or from Medieval Latin perca, Old French perce, variant of perche.
"prop, support, pole used to propel a boat," late 15c., a word of uncertain origin, perhaps from Old French poi, poie, variants of pui, puie "a railing, balustrade, trellis." Poi-tre "frame used to stretch clothes" is attested in English from late 14c.
"sloping timber of a roof," c. 1200, from Old English ræftras (West Saxon), reftras (Mercian), both plural, "a beam, pole, rafter of a building," related to Old Norse raptr "log," from Proto-Germanic *raf-tra-, from PIE *rap-tro-, from root *rep- "stake, beam."
"long pole on a ship, secured as the lower end to the keel, to support the yards, sails, and rigging in general," Old English mæst, from Proto-Germanic *mastaz (source also of Old Norse mastr, Middle Dutch maste, Dutch, Danish mast, German Mast), from PIE *mazdo- "a pole, rod" (source also of Latin malus "mast," Old Irish matan "club," Irish maide "a stick," Old Church Slavonic mostu "bridge").
The single mast of an old ship was the boundary between the quarters of the officers and those of the crew, hence before the mast "serving as an ordinary seaman" in the title of Dana's book, etc.
In all large vessels the masts are composed of several lengths, called lower mast, topmast, and topgallantmast. The royalmast is now made in one piece with the topgallantmast. A mast consisting of a single length is called a pole-mast. In a full-rigged ship with three masts, each of three pieces, the masts are distinguished as the foremast, the mainmast, and the mizzenmast; and the pieces as the foremast (proper), foretopmast, foretopgallantmast, etc. In vessels with two masts, they are called the foremast and mainmast; in vessels with four masts, the aftermast is called the spanker-mast or jigger-mast. [Century Dictionary, 1895]
Middle English rode, "a cross; a crucifix," especially a large one, from Old English rod "cross," especially that upon which Christ suffered, from Proto-Germanic *rod- (source also of Old Saxon ruoda "stake, pile, cross," Old Norse roða, Old Frisian rode, Middle Dutch roede, Old High German ruota, German Rute "rod, pole"), which is of uncertain origin. Perhaps it shares a PIE root with Latin ratis "raft," retae "trees standing on the bank of a stream;" Old Church Slavonic ratiste "spear, staff;" Lithuanian reklės "scaffolding," but de Vaan is doubtful. Probably not connected with rod.
Also in Old English "a pole;" and in Middle English also a local measure varying from 6 to 8 yards and a square measure of land.