Two or more words that mean the same thing (or almost the same thing) are called synonyms.
Two words that mean the opposite thing are called antonyms.
Sometimes, two words sound the same, or are spelled the same, but they have different meanings. These are called homonyms. Look at this sentence:
- A fly can fly very fast.
The word “fly” is used twice in this sentence, but it means two different things! “Fly” can mean a small black insect OR the verb “to fly”. Here are some more examples:
- Bat
- Mouse
- Lie
- Glass