The difference between the two words is that while both are adjectives obviously referring to poetry, 'poetic' refers to the poetry itself whereas 'poetical' can also refer to associated meanings beyond poetry proper. For example these sentences: He described the incidents poetically.

The poetic books of the Old Testament—Job, Psalms, Proverbs, Ecclesiastes, and the Song of Solomon—are often called humankind's reach toward God. The other books of the Old Testament picture God's reach toward man through the redemptive story.

The Poetic Books, also called the Sapiential Books, are a division of the Christian Bible grouping 5 or 7 books (depending on the canon) in the Old Testament. The term "Sapiential Books" refers to the same set, although not all the Psalms are usually regarded as belonging to the Wisdom tradition.

Keats sets out upon his definition of the poetical character with a paradox which is playful and perhaps not far from a joke: for there is something very puzzling in beginning a definition of anything with the observation that 'itself … it is not itself', and then going on to say that this 'character' has 'no character ...