Merriam-Webster's Collegiate® Dictionary, 11th Edition
TACK
I. verb
Etymology: Middle English takken, from tak
Date: 14th century
transitive verb attach , to join in a slight or hasty manner,
3. to add as a supplement, to add (a rider) to a parliamentary bill, to change the direction of (a sailing ship) when sailing close-hauled by turning the bow to the wind and shifting the sails so as to fall off on the other side at about the same angle as before, intransitive verb
1. to tack a sailing ship, to change to an opposite tack by turning the bow to the wind, to follow a course against the wind by a series of tacks,
2. to follow a zigzag course, to modify one's policy or attitude abruptly, tacker noun
II. noun
Etymology: Middle English tak fastener, rope tying down the windward corner of a sail, from Middle French (Norman dialect) taque; akin to Middle Dutch tac sharp point
Date: 1574
a small short sharp-pointed nail usually having a broad flat head,
2. the direction of a ship with respect to the trim of her sails , the run of a sailing ship on one tack, a change when close-hauled from the starboard to the port tack or vice versa, a zigzag movement on land, a course or method of action, any of various usually temporary stitches, the lower forward corner of a fore-and-aft sail, a sticky or adhesive quality or condition,
III. noun
Etymology: origin unknown
Date: 1841
hardtack 1,
IV. noun
Etymology: perhaps short for tackle
Date: 1924
stable gear