amphibrachys

Four groups, each practically uttered as one word: the first, in this case, an iamb; the second, an amphibrachys; the third, a trochee; and the fourth, an amphimacer; and yet our schoolboy, with no other liberty but that of inflicting pain, had triumphantly scanned it as five iambs.

Essays in the Art of Writing Robert Louis Stevenson 1872