mon·o·gram 
(mŏnə-grăm′)
(mŏnə-grăm′)n.
A design composed of one or more letters, typically the initials of a name, used as an identifying mark.
tr.v. mon·o·grammed, mon·o·gram·ming, mon·o·grams also mon·o·gramed or mon·o·gram·ing
To mark with a design composed of one or more letters.
[Late Latin monogramma, from Late Greek monogrammon, from neuter of monogrammos, consisting of a single letter : Greek mono-, mono- + Greek gramma, letter; see -GRAM.]
mon′o·gram·matic (-grə-mătĭk) adj.
monogram