Name for first line of something

Question

Is there a term for the first line of something, whether it's a poem, song, or prose?

Addendum: Sometimes, though not always, the first line is the same as the title, such as in Walt Whitman’s poem “I Sing the Body Electric”.

Answer 1

Incipit:

• The opening words of a text, especially when used in place of a title to identify an otherwise untitled work. (AHD)