Related Clues:

• Single beginning
• Directional prefix
• Verse starter
• Prefix for 'both'
• Prefix with ''brow''
• Both, for openers
• Prefix for ''cycle'' or ''form''
• Prefix for lateral
• Cycle or lateral preceder
• Start for ''corn'' or ''form''
• Both, in the beginning
• Verse intro?
• Two-thirds of sesqui-
• Kin of mono-
• Sea urchin, at a sushi bar