What is a word having same spelling but different sound and meaning?

A word having the same spelling but a different sound and meaning is called a heteronym.

Heteronyms are a special type of homograph: words written identically but pronounced differently. For example, “lead” can be pronounced “led” when it means the metal, or “leed” when it means to guide. Likewise, “tear” can mean a drop from the eye or the act of ripping something, depending on pronunciation and meaning.

Heteronyms are often confused with homophones. Homophones sound alike but may have different spellings and meanings, such as “right” and “write.” Homographs share spelling, but not all homographs have different pronunciations. “Date,” for example, can refer to a calendar day or a social meeting while usually keeping the same pronunciation.

The term comes from Greek roots meaning “different name.” English has many heteronyms because spelling often preserves historical forms even as pronunciation and meaning change. Context usually tells readers which pronunciation and definition is intended.