What is the meaning of theme in poetry?

Theme-a salient abstract idea that emerges from a literary work's treatment of its subject‐matter; or a topic recurring in a number of literary works. While the subject of a work is described concretely in terms of its action (e.g. 'the adventures of a newcomer in the big city'), its theme or themes will be described in more abstract terms (e.g. love, war, revenge, betrayal, fate, etc.). The theme of a work may be announced explicitly, but more often it emerges indirectly through the recurrence of motifs :)