A small nail with a flat head. / A thumbtack. / (sewing) A loose seam used to temporarily fasten pieces of cloth.

To nail with a tack (small nail with a flat head). / To sew/stitch with a tack (loose seam used to temporarily fasten pieces of cloth).

A stain; a tache. / (obsolete) A peculiar flavour or taint.

(colloquial) That which is tacky; something cheap and gaudy.

(law, Scotland and Northern England) A contract by which the use of a thing is set, or let, for hire; a lease.

present participle of tack

(sewing) Loose temporary stitches in dressmaking etc. / (nautical) The act of changing tack.

simple past tense and past participle of tack

plural of tack

Third-person singular simple present indicative form of tack