How many words start with BY?

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

What is the highest scoring word that start with BY?

BYWAY at 16 points in Scrabble, and BYKED at 15 in Words With Friends, because the two games score the tiles differently.

BYDED, BYDES, BYKED, BYKES, BYLAW, BYRES, BYRLS, BYSSI, BYTES, BYWAY.

There are 10 of them. The highest scoring is BYWAY at 16 points in Scrabble, and the set averages 12.1.

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.

BYTES noun form of BYTE: a sequence of 8 bits (enough to represent one character of alphanumeric data) processed as a single unit of information
BYLAW noun a rule adopted by an organization in order to regulate its own affairs and the behavior of its members
BYRES noun form of BYRE: a barn for cows
BYWAY noun a side road little traveled (as in the countryside)

Definitions from Open English WordNet, CC BY 4.0.

All of them: Word lists.