Post-it

n.

Also Post-it note.

A piece of stationery with a readherable strip of adhesive on the back, designed for temporarily attaching notes to documents, computer displays and so forth.

The names "Post-it" and "Post-it note" are trademarks of 3M, the company which invented and manufactures them. Accepted generic terms for competitors include "sticky notes" or "repositionable / repositional notes."