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

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

The process happens at an incredibly slow rate -- roughly a millionth the speed of a snail.

From Science Daily

According to the new study, this would require achieving an angular resolution of less than one millionth of an arcsecond -- roughly equivalent to spotting a coin on the surface of the Moon from Earth.

From Science Daily

This plasma is a form of matter thought to have filled the universe only millionths of a second after the big bang, the event that marks the universe's origin and expansion.

From Science Daily