Related Clues:

• Opening letter
• The bee in one's bonnet?
• Primary part of a monogram
• Grass taken up, inhaling drug — wow man!
• Endorse a letter of introduction
• Yes, truly an aspiration
• Roman two with Latin twist to start with
• I agree!
• Beginning - a letter
• First - opening
• Letter - opening
• Beginning - first letter
• Positive (or sceptical) exclamation
• First letter of a name
• Exclamation of agreement (or doubt!)