 Lewis (1946, Chps. 3, 6) distinguished several modes of meaning in AKV. The denotation of a term is the class of actual things to which the term applies and is distinct from the comprehension — the class of possible or consistently thinkable things to which it applies. The signification of a term is the property the presence of which in a thing makes the term applicable, and the intension or connotation of a term is what is applicable to any possible thing to which the term is applicable. Intension can be linguistic intension or meaning, in which case it is the conjunction of terms applicable to any possible thing to which the term is applicable and thus substitutable for the term salva veritate. However, since definitions must have criteria of application and these must ultimately be non-circular, the more basic dimension of intension is sense meaning. Sense meaning is the criterion in mind in terms of sense experience for classifying objects and applying a term-- a schema or rule that speakers have in mind whereby a term applies to an actual or thinkable thing or signifies some property, and which would exist even if there were no linguistic expression for it.