Synonym and Homonym

Synonym is the word that means the same as another word.

joyful, merry, happy.

1. I wish you a happy birthday.
2. I wish you a merry Christmas.
3. I wish you a joyful vacation.

Homonyms are the words that pronounced or spelled the same way but have different meanings.
Left, Left

• I left school at three o'clock from the left wing.
  

Life, Life

• The old man has a long life of a hundred and ten.
• He spends his whole life in prison.