Perception is how you see, hear, feel, or understand things.
Perception is about how people understand the world, so it's a very important word.
Examples:
My perception of the picture is that it's beautiful.
Her perception of the music is that it's too loud.
His perception of the story is different from mine.
The cat's perception of the toy is that it's a mouse.
My perception of time is that it goes very slowly when I'm bored.
The dog's perception of the mailman is that he's a threat.