How many words start with UM?

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

What is the highest scoring word that start with UM?

UMIAQ at 16 points in Scrabble, and UMIAQ at 18 in Words With Friends, because the two games score the tiles differently.

UMAMI, UMBEL, UMBER, UMBLE, UMBOS, UMBRA, UMBRE, UMIAC, UMIAK, UMIAQ and 8 more on this page.

18 of them: UMAMI, UMBEL, UMBER, UMBLE, UMBOS, UMBRA, UMBRE, UMIAC, UMIAK, UMIAQ and more.

There are 18 of them. The highest scoring is UMIAQ at 16 points in Scrabble, and the set averages 9.9.

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

The most familiar words on this page and what they mean. Tap any word for its full entry, score and anagrams.

UMBEL noun flat-topped or rounded inflorescence characteristic of the family Umbelliferae in which the individual flower stalks arise from about the same point
UMBER noun an earth pigment
UMBOS noun form of UMBO: a slight rounded elevation where the malleus attaches to the eardrum
UMBRA noun a region of complete shadow resulting from total obstruction of light

Definitions from Open English WordNet, CC BY 4.0.

All of them: Word lists.