Abstract The reconstruction of the culture of play and games in antiquity involves many problems of an exegetical nature, which are especially difficult to analyse because of the limited amount of encyclopaedic evidence that might provide adequate overviews and descriptions. Julius Pollux’s lexicon is an essential text in this regard. In the second half of the second century AD he wrote a synthesis of ancient knowledge, in which each notice was presented within very specific rhetorical and discursive constraints. This article focuses specifically on a passage (Poll. 9.100) in which two different names are given to the same face of the knucklebone. This passage presents an interpretative problem that has led some scholars to hypothesize a specific game rule. This paper shows how the answer to such an exegetical aporia can be solved by looking at the rhetorical specificities of the lexicographic genre and in particular at the discursive organization of the onomastic knowledge by Pollux.