Verbal note
Black's Law Dictionary · Henry Campbell Black, M.A. · 1910
Black's Law Dictionary
A memorandum or note, in diplomacy, not signed, sent when an affnir has continued a long time without any reply, in order to avoid the appearance of an urgency which perhaps is not required; and, on the other hand, to guard against the supposition that it is forgotten or that there la an intention of not prosecuting it any further.
Wharton.