iambic + -ally, or iambical + -ly
iambically (comparative more iambically, superlative most iambically)
- According to iambic meter.
2001, David Keppel-Jones, The strict metrical tradition, page 27:
First, English phrases tend to open iambically on an unstressed word (article, preposition, or conjunction), as with The rising world and the waters in the line before us.