amphibrach
noun
am·phi·brach ˈam(p)-fə-ˌbrak 
: a metrical foot consisting of a long syllable between two short syllables in quantitative verse or of a stressed syllable between two unstressed syllables in accentual verse
romantic is an accentual amphibrach
amphibrachic
ˌam(p)-fə-ˈbra-kik
adjective 
Word History
Etymology
borrowed from Latin amphibrachys, borrowed from Greek amphíbrachys, from amphíbrachys, adjective, "short at both ends," from amphi- amphi- + brachýs "short" — more at brief entry 1
First Known Use
1765, in the meaning defined above