In later medieval logic, a term referring to the substitutionary value that a subject of a proposition takes in relation to its predicate.  The suppositio of a term determines what the term itself refers to: for example, materially to the word itself being used; a general notion; a particular individual; some determinate or indeterminate individual; a group of individuals; etc.  Theories of supposition are important to a number of aspects of modern logic where the latter distinguishes between the sense of a term and its reference.