i Register
In some senses, eleventy is marked as informal, colloquial. Watch for register when choosing this word.
num
The number 110, 11 × 10.
Compounds with other numerals: eleventy-one (111), eleventy-six (116), eleventy first (one-hundred and eleventh), etc.
[Bilbo] announced that he would shortly be celebrating his eleventy-first birthday […] “Today is my one hundred and eleventh birthday: I am eleventy-one today!”
An indefinite large number.
No grown-up people, no babies, no girls. It was a world of boys, eleventy and a hundred strong.
People used to think that the first eleventy letters of the DNA message would comprise Gene 1.