adj. Next in order after nine hundred and ninty-nine; coming last of a thousand successive individuals or units; -- the ordinal of thousand.adj. Constituting, or being one of, a thousand equal parts into which anything is divided; the tenth of a hundredth.adj. Occurring as being one of, or the last one of, a very great number; very small; minute; -- used hyperbolically.n. The quotient of a unit divided by a thousand; one of a thousand equal parts into which a unit is divided.