How many words start with ON?

14, from 5 letters up to 5. All of them are on this page.

What is the highest scoring word that start with ON?

ONKUS at 9 points in Scrabble, and ONKUS at 11 in Words With Friends, because the two games score the tiles differently.

ONCER, ONCES, ONCET, ONCUS, ONELY, ONERS, ONERY, ONION, ONIUM, ONKUS and 4 more on this page.

14 of them: ONCER, ONCES, ONCET, ONCUS, ONELY, ONERS, ONERY, ONION, ONIUM, ONKUS and more.

There are 14 of them. The highest scoring is ONKUS at 9 points in Scrabble, and the set averages 6.9.

Most common words first, then the rest A to Z.

All of them: Word lists.