Mill'ionth1, a.
a. Being the last one of a million units or objects counted in regular order from the first of a series or succession; constituting one of a million.
2 entries under this word
a. Being the last one of a million units or objects counted in regular order from the first of a series or succession; constituting one of a million.
n. The quotient of a unit divided by one million; one of a million equal parts.