 Probabilis was the most important probability-related predicate in the Middle Ages (and in the whole scholastic tradition). It is often possible to translate probabilis as ‘probable’ in an ordinary language sense, but attention should be paid to meanings arising from a combination with particular nouns. The predicate probabilis mainly pertained to propositions, sentences, or opinions, but these are not the only meaningful referents. Sometimes persons were described as probable, as in the phrase “the more probable philosophers” (philosophi probabiliores). Thomas Deman (1933, 262) renders this phrase as “the philosophers who deserve most consideration”; but one could also translate it as “the philosophers who are more likely to find the truth”. Signs were also sometimes called probable (signum probabile), as in Silvester de Prierio’s Summa under the heading ‘probabile’. Last but not least, probability was attributed to events, for instance, when Thomas Aquinas, in Summa theologiae II-II, q. 32, 5, 1322, says “according as things probably and generally occur / according to what probably and generally occurs” (secundum ea quae probabiliter et in pluribus occurrunt). As we shall see, however, it is conceivable that all these assertions are elliptic references to the probability of propositions.