As nouns the difference between millionth and microunit
is that millionth is the person or thing in the millionth position while microunit is one millionth of any standard unit (especially of an si unit).
As an adjective millionth
is the ordinal form of the number one million.
millionth
English
Adjective
(-)
The ordinal form of the number one million.
Synonyms
* 1,000,000th, 1,000,000th
Noun
(
en noun)
The person or thing in the millionth position.
One of a million equal parts of a whole. Term ppm (parts per million) is also used.
microunit
English
Noun
(
en noun)
One millionth of any standard unit (especially of an SI unit)