Possible Clues:

• Part of year depicted in end of sonnet by old poet
• Period when expecting con­clusion from beat poet
• Canopy closing off border for three months
• Merit rest — could be three months
• One term is confused with another shorter one
• Three months guarding border's a tricky problem
• Someone trying to bag skirt for school term
• Academic term
• Neat girl missing hard term in US university
• Examiner biting lip in term time