How many words start with MET?

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

What is the highest scoring word that start with MET?

METHO at 10 points in Scrabble, and METIC at 11 in Words With Friends, because the two games score the tiles differently.

METAL, METED, METER, METES, METHO, METHS, METIC, METIF, METIS, METOL and 2 more on this page.

12 of them: METAL, METED, METER, METES, METHO, METHS, METIC, METIF, METIS, METOL and more.

There are 12 of them. The highest scoring is METHO at 10 points in Scrabble, and the set averages 8.0.

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.

METAL noun any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc.
METER noun the basic unit of length adopted under the Systeme International d'Unites (approximately 1.094 yards)
METRO noun an electric railway operating below the surface of the ground (usually in a city)
METRE noun the basic unit of length adopted under the Systeme International d'Unites (approximately 1.094 yards)
METES noun form of METE: a line that indicates a boundary
METHS noun form of METH: an amphetamine derivative (trade name Methedrine) used in the form of a crystalline hydrochloride
METIC noun an alien who paid a fee to reside in an ancient Greek city

Definitions from Open English WordNet, CC BY 4.0.

All of them: Word lists.