homograph
A word that shares spelling with another but means something different.
A homograph is a word that's spelled exactly the same as another word but has a completely different meaning, and sometimes a different pronunciation too.
Consider the word “bow.” When you bow (sounds like “cow”) to show respect, you're bending at the waist. But when you tie a bow (sounds like “go”) on a present, you're making a decorative knot. Same spelling, different meanings, different sounds. That's a homograph.
Some homographs sound identical but mean different things. The word “bat” could mean a flying mammal or a piece of sports equipment. “Fair” might describe a carnival or something that's just and equal. When you read “lead,” you have to use context to know whether someone will lead (sounds like “feed”) the way or if something is made of lead (sounds like “fed”), the metal.
Homographs can create confusion in reading, especially for people learning English, but context usually makes the meaning clear. When you see “I saw a bat,” the rest of the sentence tells you whether someone spotted a flying creature or picked up a piece of sports equipment.