Read the dictionary definition of forget. All definitions for this word.
1. be unable to remember
1. I'm drawing a blank
2. You are blocking the name of your first wife!
2. dismiss from the mind; stop remembering
1. I tried to bury these unpleasant memories
3. leave behind unintentionally
1. I forgot my umbrella in the restaurant
2. I left my keys inside the car and locked the doors
4. forget to do something
1. Don't forget to call the chairman of the board to the meeting!
See also: Merriam-Webster definition of forget