millionth

American  

[mil-yuhnth] / ˈmɪl yənθ /

adjective

1. coming last in a series of a million.

2. being one of a million equal parts.

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noun

1. the millionth member of a series.

2. a millionth part, especially of one (1/1,000,000).

millionth British  

/ ˈmɪljənθ /

noun

1. 1. one of 1 000 000 approximately equal parts of something

   2. ( as modifier )

      a millionth part

2. one of 1 000 000 equal divisions of a particular scientific quantity

3. the fraction equal to one divided by 1 000 000

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adjective

1. (usually prenominal)

   1. being the ordinal number of 1 000 000 in numbering or counting order, etc

   2. ( as noun )

      the millionth to be manufactured

Etymology

Origin of millionth

First recorded in 1665–75; million + -th ²

Example Sentences

These little red dots emit much of their light at wavelengths longer than a 10 millionth of a meter, in the mid-infrared.

From Science Daily • Nov. 29, 2025

This year, Amazon deployed its millionth robot, and treated the fleet to a new data model that improved travel time by 10%.

From Barron's • Nov. 26, 2025

In a video posted Sunday, the “After Hours” performer said, “I’m being asked and called to clarify and make a statement yet again for the millionth time that I am not antisemitic nor anti-Jew.”

From Los Angeles Times • Apr. 28, 2025

Few forces are more formidable than a Black woman who’s been wronged – again, and for the millionth time – and decides that this time they’re not letting it slide.

From Salon • Apr. 2, 2024

Isabella and I find a spot on the pokey grass, and just as I’m rearranging my beret for the millionth time, I see Julia.

From "A Good Kind of Trouble" by Lisa Moore Ramée