This article is about the figure poem Egg by Simias of Rhodes, a concrete poem known for its visual arrangement in the shape of an egg, extraordinary metrical composition, sophisticated paronomasia and puns on metrical termini technici. The question this article explores is what can be learned from Simias’s verses about the metrical terminology of the late 4th and early 3rd century BC. The poet himself gives instructions in lines 9–10 how his poem should be arranged for reading, with the lines increasing in length from one foot to ten. My suggestion is that Simias’s Egg, in the form of an extended pun, might indirectly provide an overview of some metrical terms that were in use during his time: foot, kolon, metron, rhythmus, etc. Simias’s use of the word κῶλα, in the so-called “dancing fawns” comparison (l. 13), is particularly sophisticated, alternating its connotation between that of ‘limb’, ‘foot, leg’ and ‘a metrical unit’. I propose a list of “metrical” words which Simias used directly or metaphorically and which occur later in Hephaestion’s Enchiridion as metrical terms. We possess neither the treatises on which Hephaestion built his Enchiridion nor the names of his direct predecessors. Metrical terminology proves to be quite conservative, and some terms, which Simias used in his Egg and Hephaestion in the Enchiridion, are still in use today as standard metrical terms. Almost all of these terms can be found in the Nomenclator Metricus written by Otto Schroeder (1929). The poem is full of allusions and obscure metaphors later typical of Hellenistic epigrammatic poetry, in particular, the poem’s sophisticated wordplay on metrical terminology.