Thou'sandth1, a.
a. 1. Next in order after nine hundred and ninety-nine;—the ordinal of thousand; as, the thousandth part of a thing.
Sense 2. Constituting or being one of a thousand equal parts into which any thing is divided.
Sense 3. Hence, occurring as, or being one of, a very great number; very small; minute;—used proverbially; as, to do a thing for the thousandth time.