— billionth , adj. , n.
/bil"yeuhn/ , n. , pl. billions , ( as after a numeral ) billion , adj.
n.
1. a cardinal number represented in the U.S. by 1 followed by 9 zeros, and in Great Britain by 1 followed by 12 zeros.
2. a very large number: I've told you so billions of times.
adj.
3. equal in number to a billion.
[ 1680-90; b ( i )- BI- 1 + -illion, as in million ]