1. One who lags; that which comes in last. The lag of all the flock.
2. The fag-end; the rump; hence, the lowest class. The common lag of people. (Shak)
3. The amount of retardation of anything, as of a valve in a steam engine, in opening or closing.
4. A stave of a cask, drum, etc.
(Science: machinery) Especially, one of the narrow boards or staves forming the covering of a cylindrical object, as a boiler, or the cylinder of a carding machine or a steam engine.
5. (Science: zoology) see graylag. Lag of the tide, the interval by which the time of high water falls behind the mean time, in the first and third quarters of the moon; opposed to priming of the tide, or the acceleration of the time of high water, in the second and fourth quarters; depending on the relative positions of the sun and moon. Lag screw, an iron bolt with a square head, a sharp-edged thread, and a sharp point, adapted for screwing into wood; a screw for fastening lags.