A poet's lexicon is the body of words and phrases that tend to appear in that poet's work, or in the language of a particular poem, style, or literary period. It includes recurring diction, favored images, and characteristic word choices that help shape the poem's voice and tone.
Writers and readers may talk about a poet's lexicon to describe a recognizable vocabulary, such as plain everyday speech, religious language, or words drawn from nature, work, or folklore.
Example
Her lexicon leans toward salt, sail, harbor, and gull,
so even her love poems seem to arrive by tide.