slack Obs.
n. thread.
- 1852  I guess if you won't lend me the gown, you will let me have some black slack to quilt a stuff petticoat, a quarter of a pound of tea and some sugar; and I will bring them back as soon as I can.
- 1863  A store where everything was sold, from a nail or a spool of 'slack' to a keg of spirits or an almanac. . . .