A variant form of a grapheme as `m' or `M'

• A signature made by one person for another

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Allograph \Al"lo*graph\, n. [Gr. ? another + -graph.] A writing or signature made by some person other than any of the parties thereto; -- opposed to autograph .

WordNet Word definitions in WordNet
n. a variant form of a grapheme as `m' or `M' a signature made by one person for another

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
"writing made by another person," by 1916 (implied in allographic ), from allo- + -graph "something written."

Wiktionary Word definitions in Wiktionary
n. 1 A variant form of a letter (or other grapheme) 2 A signature made by one person for another (compare autograph)