Pronunciation: (thou'zundth, -zuntth, -zunth),[key] —adj. 1. last in order of a series of a thousand.
2. being one of a thousand equal parts.
—n. 1. a thousandth part, esp. of one (1/1000).
2. the thousandth member of a series.
3. Also,thou'sandth's place".(in decimal notation) the position of the third digit to the right of the decimal point.