Coill (plural coillte) represents the forest as both physical reality and imaginative space in Irish verse. Ireland's ancient forests were largely destroyed over centuries of colonisation and agricultural clearance, making the coill a nostalgic and elegiac term as much as a descriptive one. In early Irish nature poetry the wood is a place of beauty and spiritual clarity; in later verse it becomes an image of what has been lost. The wild man of the woods — as in Buile Shuibhne — finds his true home in the coill, and the tradition of hermit poetry from early Christian Ireland celebrates the forest as a place of divine encounter.

Coill (wood/forest) in Irish poetry is a place of refuge, mystery, and wildness. It is associated with the fianna (warrior bands) who lived outside societal norms in the forest. The coill is also a site of spiritual retreat for poets seeking inspiration away from human settlement. Deforestation is a recurring theme of loss in modern Irish poetry, where the coill represents a vanished natural heritage. Poets use coill imagery to explore themes of isolation, protection, and the untamed aspects of nature.