Possible Clues:

• Group of lines of verse
• On its feet, a bit of poetry
• One of four for 'The Star-Spangled Banner'
• 'Bears a bit inversely, by the sound of it (6)'
• Poetic subunit
• Poetry unit
• Somehow Santa admits last letter reads like a poem
• Fixed number of lines of verse
• 'By the sound of it, there stands a bit of poetry (6)'
• Verse in poetry