thousandth

American  

[thou-zuhndth, -zuhntth, -zuhnth] / ˈθaʊ zəndθ, -zəntθ, -zənθ /

adjective

1. last in order of a series of a thousand.

2. being one of a thousand equal parts.

---

noun

1. a thousandth part, especially of one (1/1000).

2. the thousandth member of a series.

3. Also thousandth's place (in decimal notation) the position of the third digit to the right of the decimal point.

thousandth British  

/ ˈθaʊzənθ /

adjective

1. (usually prenominal)

   1. being the ordinal number of 1000 in numbering or counting order, position, time, etc

   2. ( as noun )

      the thousandth in succession

---

noun

1. 1. one of 1000 approximately equal parts of something

   2. ( as modifier )

      a thousandth part

2. one of 1000 equal divisions of a particular scientific quantity

   millivolt

3. the fraction equal to one divided by 1000 ( 1/ 1000 )

Etymology

Origin of thousandth

First recorded in 1545–55; thousand + -th ²

Example Sentences

Any parent who has read a “Berenstain Bears” book aloud under duress for the thousandth time will know what I mean.

From The Wall Street Journal • Dec. 12, 2025

In the Milky Way, only the central nucleus has star densities remotely comparable, and that region still contains only about one thousandth of the stars needed for the little-red-dot models.

From Science Daily • Nov. 29, 2025

He was gifted with a superhuman taste sensitivity: He could easily distinguish a flavor at one ten thousandth of a gram in a fifteen ton batch.

From Salon • Nov. 7, 2024

The show, a staple of the WWE’s TV schedule, has been three hours long since its thousandth episode aired in July 2012.

From BBC • Sep. 10, 2024

And of myself—older, too, sitting around with him in some smoky room, the two of us repeating this exchange for the thousandth time.

From "The Secret History" by Donna Tartt