a sign, motif, or symbol, typically made up of a person's initials written in a decorative way, used to mark or identify someone's personal belongings;
e.g. The handkerchief had a monogram in one corner, bearing the letter "M".
(verb)
to mark or decorate something with a symbol consisting of someone's initials;
e.g. She will monogram her initials on the lapel of the coat.