From Longman Dictionary of Contemporary Englishdrop somebody a line/notedrop somebody a line/noteTCN informal to write a short letter to someone Drop us a line to let us know how you’re getting on. → drop
Examples from the Corpus
drop somebody a line/note• If he can not do so, perhaps he will drop me a line.• Keep a folder on your desk, and during the year drop in notes about the special things you did.• She pulled open a drawer to drop the note in.• The telephone isn't connected yet but you can drop a note in.• Other cities have dropped their line items without allowing departments to keep any of their savings.• Do drop me a line, Mrs Surridge, or anyone else who's interested.• Drop us a line sometime.• After the people have been touched, they drop a £10 note, the usual donation, on the small table.• Just wanted to drop you a note to say break a leg and all those other theatrical cliches. 