And both relate to the form of a poem?

Answer 1

Technically they are not.

Poetry is the all encompassing genre of the written and spoken word that exists in the form of verse.

Poetic form is the manner or style in which it exists.

Answer 2

Sonnet and haiku are both forms of poetry. A sonnet is a 14-line poem with a specific rhyme scheme and structure, typically written in iambic pentameter. A haiku, on the other hand, is a three-line poem with a syllable pattern of 5-7-5, traditionally focusing on nature or a moment of brief insight.

Answer 3

Rhyme scheme and stanza both relate to the form of a poem.