Definition of "octosyllabic"

octosyllabic

/ˌɒk.təʊ.sɪˈlæb.ɪk/

adjective
not comparable
1. Containing eight syllables
  Quotations
  If you hum or whistle the rhythm of the common English metres,— of the decasyllabic quatrain, or the octosyllabic with alternate sexisyllabic, or other rhythms, […]
  1872, Ralph Waldo Emerson, Poetry and Imagination