Definify.com

Webster 1913 Edition

Noun.

A character or vocal sign representing more than one sound, as read, which is pronounced rēd or rĕd.

polyphone ‎(plural polyphones)

A letter, or combination of letters, that can be pronounced in two or more different ways

polyphone

Chinese:
Mandarin: 多音字 (zh) ‎(duōyīnzì) (homograph, refers to characters with more than one reading)