If you know something memoriter, you know it by heart, without needing to look at it.
Knowing something memoriter can make people think of being very smart or of working very hard to remember something.
Examples:
She recited the poem memoriter.
He learned the song memoriter.
The children sang the song memoriter at the concert.
I can say the alphabet memoriter!
He knows the whole book memoriter, even the hard words.
I can say the whole poem memoriter, just like a teacher!