Related Clues:

• Open with a box cutter
• Buttonhole, say
• Opening centre with parking for 100
• Bead source
• Cut with a razor blade
• Transpiration opening
• With 11-Down, study intently
• Pupil of a lizard, e.g
• 37 Across feature
• Not much light can get through it
• Opening on a sweater?
• X-Acto knife cut, perhaps
• Cut some tasteless literature
• Use an X-Acto Knife on
• Cat's pupil, on a sunny day