Real Dictionary

English muffin
countable noun: English muffins are flat, round bread rolls that you split in half and usually eat hot with butter.

English muffin in American English
a large, somewhat flat yeast roll, often baked on a griddle, and served split and toasted
noun: a rather flat muffin made from yeast dough, typically baked on a griddle, and then split and toasted before being eaten

English muffin in British English
noun: bread dough rolled and cut into rounds, baked on a griddle, and split and toasted just before eating