monogram

Short definition from Wiktionary

Noun

1. 1
   A picture drawn in line only, before the colour and/or shading is applied; an outline sketch.
2. 2
   A sentence consisting of only one line, or an epigram consisting of only one verse, of poetry.
3. 3
   A design or motif composed of one or more letters, often intertwined, used as an identifying mark of an individual or institution; the letters are usually the initials of their names.
4. 4
   One of the symbols used in either the I Ching divination or the Taixuanjing divination: the unbroken line ⚊ for Heaven;
5. 5
   One of the symbols used in either the I Ching divination or the Taixuanjing divination: the once-broken line ⚋ for Earth;
6. 6
   One of the symbols used in either the I Ching divination or the Taixuanjing divination: the twice-broken line 𝌀 for Man (only used in Taixuanjing divination).

Verb

1. 1
   To mark something with a monogram.