Related Clues:

• Angular prefix
• Athlete's outfit, casually
• Cellular opening?
• Start to fold?
• Prefix for cycle or angle
• One more than "bi"
• Prefix before brow
• Plex preceder
• Tetra- minus 1
• Prefix meaning "one"
• It may precede sex
• Lateral intro
• Beginning for "lateral"
• Valve opening?
• Single at the beginning?