Digital Companion to C. S. Peirce
1903 | A Syllabus of Certain Topics of Logic | CP 4.395

A graph is the propositional expression in the System of Existential Graphs of any possible state of the universe. It is a Symbol, and, as such, general, and is accordingly to be distinguished from a graph-replica. A graph remains such though not actually asserted.

1903 | Lecture II [R] | MS [R] 455:4

The mathematicians call a diagram that is composed mainly of spots of different kinds and of lines, a graph.

1903 | A Syllabus of Certain Topics of Logic | CP 4.414

A graph is a legisign (i.e., a sign which is of the nature of a general type) which is one of a certain class of signs used in this system [of existential graphs].

1903 [c.] | Logical Tracts. No. 1. On Existential Graphs | MS [R] 491:1

A Graph is a diagram consisting of no more than, first, the sheet upon which it is written, secondly, spots (or their equivalents) having various visible qualities (as colors, etc), third, lines of connection (commonly of only two kinds, those that are drawn and those that are left undrawn), and fourth[,] enclosing ovals.

1903 [c.] | Logical Tracts. No. 2. On Existential Graphs, Euler's Diagrams, and Logical Algebra | CP 4.419

A graph is a superficial diagram composed of the sheet upon which it is written or drawn, of spots or their equivalents, of lines of connection, and (if need be) of enclosures. The type, which it is supposed more or less to resemble, is the structural formula of the chemist.