The role of kenning in poetry is related to describing an object in an alternative way in order to provide a different and often richer meaning for that object to an audience. Kenning is a poetic technique that goes back to ancient Anglo-Saxon and Norse poetry. It is well represented in classics like Beowulf, and in other Old English works.
Experts describe kenning as a compressed metaphor, which means that a relational meaning is expressed with just a few words. Typically, poets that use kenning use a compound word, often with a hyphen, to describe an object. In a more conventional metaphor, a greater number of words would be needed to effectively convey the metaphorical meaning. For example, using the compound word phrase “fish-road” instead of the word “sea” is a prime example of kenning; here, the poet replaces a simple meaning with a complex one that suggests that the sea or ocean is a venue that provides transportation for sea creatures. In a conventional metaphor, the poet might need to write something longer like “a road for fish.”
A primary role of kenning in poetry is to use examples like the above to describe an object in more detail. The two parts of the compound word often represent a subject and object relationship that creates complex associations in a concise, and often abstract, way. Kenning is, in a most basic sense, a unique way to label an object for the meaning and presentation of a concept in poetry.
Besides being a quicker way to create metaphors, kenning is also related to dialect. In many cases, the role of kenning in poetry might be to showcase examples of local or regional dialect. In more than a few language communities, describing a simple object with a compound word phrase instead of a single word is part of a common dialect that may be unfamiliar to those outside of the community. Poetry may reflect this through the use of kenning, in order to acquaint readers with the ways that a local population uses language.
Many would say that a broader use for this kind of metaphorical phrase is to make the language of poetry more vibrant. Many academics and experts in literature suggest using kenning in poetry to inject more thought provoking vocabulary into a work. This tends to keep a readership engaged and adds to the appeal of many kinds of poetry, where more technical word choices might make the literary work seem flat and uninspired.