Abhainn (anglicised in hundreds of placenames as avon, owen, or awn) is one of the most geographically ubiquitous words in the Irish landscape, embedded in rivers from the Avonmore to the Owenmore. Its poetic use ranges from precise geographical description to broad metaphor: the river as time's passage, as the boundary between worlds, as the artery of a landscape's life. In dinnsheanchas poetry, rivers are named and their names explained through mythological narrative. The rivers of Ireland — Shannon, Boyne, Liffey — carry such dense accumulations of poetic and historical association that to name them in verse is immediately to invoke this entire tradition.

In Irish poetry, the abhainn is rarely just a physical feature; it often serves as a boundary between the mortal world and the otherworld, or as a metaphor for the flow of time and memory. Poets frequently personify rivers as female deities, drawing on ancient mythological associations where specific rivers were believed to be goddesses in their own right. When translating or analyzing verses featuring abhainn, consider its grammatical gender (feminine) and how this influences adjectival agreement and poetic imagery of nurturing or dangerous fluidity.