tack

Etymology 1

From Middle English tak, takke (“hook; staple; nail”), from Old Northern French taque (“nail, pin, peg”), from Frankish *takkō, from Proto-Germanic *takkô (“tip; point; protrusion; prong; tine; jag; spike; twig”), of unknown origin, but possibly from Proto-Indo-European *dHgʰ-n-, from the root *déHgʰ- (“to pinch; to tear, rip, fray”). Cognate with Saterland Frisian Takke (“bough; branch; twig”), West Frisian takke (“branch”), tûk (“branch, smart, sharp”), Dutch tak (“twig; branch; limb”), German Zacke (“jag; prong; spike; tooth; peak”).

noun

1. A small nail with a flat head.
   A tough test for even the strongest climber, it was new to the Tour de France this year, but its debut will be remembered for the wrong reasons after one of those spectators scattered carpet tacks on the road and induced around 30 punctures among the group of riders including Bradley Wiggins, the Tour's overall leader, and his chief rivals. 2012-07-15, Richard Williams, “Tour de France 2012: Carpet tacks cannot put Bradley Wiggins off track”, in The Guardian
2. A thumbtack.
3. (sewing) A loose seam used to temporarily fasten pieces of cloth.
4. (nautical) The lower corner on the leading edge of a sail relative to the direction of the wind.
5. (nautical) A course or heading that enables a sailing vessel to head upwind.
6. (figurative) A direction or course of action, especially a new one.
   When even cautious German politicians are questioning Nato’s ‘war-mongering’ actions, it’s clear that a new tack is required 2016-06-19, Mary Dejevsky, “Isolating Russia isn’t working. The west needs a new approach”, in The Guardian
7. (nautical) The maneuver by which a sailing vessel turns its bow through the wind so that the wind changes from one side to the other.
8. (nautical) The distance a sailing vessel runs between these maneuvers when working to windward; a board.
9. (nautical) A rope used to hold in place the foremost lower corners of the courses when the vessel is close-hauled; also, a rope employed to pull the lower corner of a studding sail to the boom.
10. Any of the various equipment and accessories worn by horses in the course of their use as domesticated animals.
11. (manufacturing, construction, chemistry) The stickiness of a compound, related to its cohesive and adhesive properties.
    The laminate adhesive has very aggressive tack and is hard to move once in place.
    Letterpress and offset gloss varnishes normally have viscosities varying from 50 to 250 poises; they must stain the paper as little as possible, have insufficient tack to cause plucking, […] 1959, E. A. Apps, Printing Ink Technology, page 415
12. Food generally; fare, especially of the bread kind.
    hardtack
    soft tack
13. That which is attached; a supplement; an appendix.
14. (obsolete) Confidence; reliance.
    He should find[…]that there was tack in it, that it was solid silver, or silver that had strength in it. 1651-1666, Joseph Caryl, Exposition of Job with Practical Observations

Etymology 2

From Middle English takken (“to attach; nail”), from the noun (see above).

verb

1. To nail with a tack (small nail with a flat head).
2. To sew/stitch with a tack (loose seam used to temporarily fasten pieces of cloth).
3. (nautical) To maneuver a sailing vessel so that its bow turns through the wind, i.e. the wind changes from one side of the vessel to the other.
4. To add something as an extra item.
   to tack (something) onto (something)
   In short, they tend to present Indian English as nothing more than "standard" English with a select collection of lexical peculiarities tacked on, as it were, many of which would be regarded as "errors" by prescriptivist language scholars. 2012, James Lambert, “Beyond Hobson-Jobson: A new lexicography for Indian English”, in World Englishes, page 312
5. To place the tack on a horse; often paired with "up".

Etymology 3

From an old or dialectal form of French tache. See techy. Doublet of tache.

noun

1. A stain; a tache.
2. (obsolete) A peculiar flavour or taint.
   a musty tack

Etymology 4

Back-formation from tacky.

noun

1. (colloquial) That which is tacky; something cheap and gaudy.
   For souvenirs – mostly outright tack and ethnicky textiles – try your bargaining skills at the shops and stalls on Binjiang Luand Zhengyang Jie, or the nightly street market spreading for about a block either side of Shanhu Bridge along Zhongshan Lu. 2014, David Leffman, The Rough Guide to China

Etymology 5

From Middle English tak, take (“fee, tax (on livestock)”), from Old Norse tak, taka (“a taking, seizure; revenue”), from Old Norse taka (“to take”). Cognate with Scots tack.

noun

1. (law, Scotland and Northern England) A contract by which the use of a thing is set, or let, for hire; a lease.
   In the Breadalbane papers, for example, there is a "tack" which was given by Sir John Campbell of Glenurchy to his "weil belouit" servant John M'Conoquhy V'Gregour, in the year 1530. 1885, Lord Colin Campbell, The Crofter in History