Two senses of ‘term’

Medieval philosophers and logicians used the word ‘term’ (terminus) in several senses, two of which are especially pertinent to this discussion. Strictly speaking, a term is what is subjected to the predicate or predicated of the subject in an ordinary categorical proposition – the subject term or the predicate term, the two ends (termini) of the proposition. In this sense whole phrases may be terms, but only certain sorts of words – nouns, adjectives, and verbs – can serve by themselves as terms. Less strictly, and in the later Middle Ages more prevalently, a term is any word at all, regardless of propositional context. In this discussion ‘term’ will be used in the less strict sense unless otherwise noted.

Signification as a psychological and causal property of terms

There are two basic properties for the medieval semantics of terms: signification and supposition. Signification is a psychologico-causal property of terms – a fact responsible for many disagreements and tensions in medieval semantics. The main source for the notion of signification was Boethius' translation of De interpretatione 3, 16b 19: ‘[Verbs] spoken in isolation are names and signify something. For he who speaks [them] establishes an understanding and he who hears [them] rests’. Hence ‘to signify’ something was ‘to establish an understanding’ of it. The psychological overtones of ‘to signify’ are similar to those of the modern ‘to mean’. Nevertheless, signification is not meaning. A term signifies that of which it makes a person think, so that, unlike meaning, signification is a species of the causal relation.