1
general::
Mark as entered, or examined and passed, as in He checked off their names as they arrived. [Early 1800s]
American Heritage Idioms
2
general::
Phrase(s): check someone or something off
to mark or cross out the name of a person or thing on a list. • I am glad to see that you were able to come. I will check you off. • I checked the items off. • I checked off the recent arrivals.
McGrawhill's American Idioms And Phrasal Verbs