The title of William Butler Yeats's poem, ‘The Second Coming,’ is significant in several ways.

Firstly, the title refers to the Christian belief in the Second Coming of Christ, which is the belief that Jesus will return to Earth to establish his Kingdom. This idea is referenced in the opening line of the poem, which describes ‘a widening gyre’ that suggests the end of one era and the beginning of another. Thus, the title is significant in that it sets up an expectation of a momentous event that will change the course of history.

Secondly, the title can be read in a more secular way as well. The phrase ‘the second coming’ can also refer to the idea of a rebirth or renewal of the world. Yeats himself saw the 20th century as a time of great change and upheaval, and the poem can be seen as a meditation on the emergence of a new world order.

Thirdly, the title can be seen as a reference to Yeats's own artistic vision. The poem can be read as a reflection on the role of the poet in a world that is in crisis. Yeats believed that the artist had a responsibility to create new forms of beauty and meaning in a world that was rapidly changing, and the title can be seen as a reference to this idea of artistic rebirth.

The title ‘The Second Coming’ is significant in that it sets up an expectation of a momentous event that will change the course of history, while also suggesting themes of rebirth, renewal, and artistic vision.