1
general::
Phrase(s): leave word (with someone)
Fig. to leave a message with someone (who will pass the message on to someone else). • If you decide to go to the convention, please leave word with my secretary. • Leave word before you go. • I left word with your brother. Didn’t he give you the message?
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Leave a message, as in Please leave word at the desk when you check out, or I left word about my plans with the secretary; didn't she tell you? This expression employs word in the sense of "information," a usage dating from the 10th century.
American Heritage Idioms