Strictly speaking, monograms and signums are not heraldry but go hand in hand in presenting the Armiger. Monogram is a single picture devised from the letters of a person's name, usually the initials. Signum means a sign and is more illusive for explanation. It is a sign representing a person, in short.
Both items are in slight collision with heraldry, as they tend to perform the same function, that of representing. Where heraldry is silent, monogram prevails and vice-versa. There are cases, especially in Russian Imperial heraldry, where monograms were often a part of Emperor's arms.
Monograms are a nice art form, but a limited one compared to heraldry. Together they are a perfect match.
My signum.
Monogram of the Tomasevic Family (Tomašević, Tomashevich)
Monogram of Kimon Andreou Vergara
