a trisyllabic foot, the arrangement of the syllables of which is short, long, short in quantitative meter, or unstressed, stressed, unstressed in accentual meter. Thus, together is an accentual amphibrach.
Origin of amphibrach
1580–90; < Latinamphibrachus < Greekamphíbrachys short before and after (amphi-amphi- + brachýs short); cf. amphimacer
1580s, from Latin amphibrachus, from Greek amphibrakhys, a foot consisting of a long syllable between two short, literally "short at both ends," from amphi- "on both sides" (see amphi-) + brakhys "short" (see brief (adj.)).