kenning - A type of metaphor. Attributed to Anglo Saxon poetry, especially Beowulf. The language of Beowulf with its four-beat alliterative line is perfect for the use of a kenning.
The criticism of kennings is that of the compound epithet, overuse. One reason students abandon the study of Beowulf is because the kennings are unfamiliar metaphors and require constant footnote referral. Of course there are standard epithets like “helmet bearers” as warriors, “earth-ball” a burial mound or barrow, “stone-cliffs” as walls of stone, and “stout-hearted” meaning bravery. But the following are kennings:
In another Anglo Saxon work, The Wanderer, the kenning “storm of spears” means battle.
kyrielle - A French form developed by troubadours of the middle ages. The distinctive feature of the kyrielle is that each stanza ends with the identical final line thus creating a refrain. The repeating of whole lines within a poem is also called "rime en kyrielle". The name kyrielle derives from the kyrie eleison (Lord have mercy), which is part of the Roman Catholic liturgy. A kyrielle is written in rhyming couplets or quatrains. It uses the phrase Lord have mercy, or a variant on it, as a refrain as the second line of the couplet or last line of the quatrain. In less strict usage, other phrases, and sometimes single words, are used as the refrain.
The rhyme scheme seems to depend on whether the poem is written in couplets or quatrains. If written in couplets the rhyme scheme is aA;aA (uppercase indicating refrain). If the kyrielle is constructed in quatrains, then in may be have a-a-b-B, c-c-b-B and a-b-a-B, c-b-c-B. In the original French kyrielle, lines were generally octosyllabic.
The English kyrielle is usually written in iambic tetrameters. It has stanzas of four lines with no set rhyming scheme but most frequently abab or aabb. The kyrielle can be of any length. A good example is Thomas Campion's (1567-1621) A Lenten Hymn. In quatrains with rhyme scheme aabB:
And another by Campion in quatrains with rhyme scheme abba. With variation in the repeated final lines: