Possible Clues:

• In sound in size or in mouth
• Part of da Vinci's oral equipment
• In the sound of the size, or in the mouth
• In however big it sounds, or afterwards, one is never given to backbiting
• Is O there, right at the front?
• By the sound of it, in size or in the mouth
• A front tooth
• Any of the four anteriors
• Ivory perhaps incorporated - is gold as well?
• The size in which it goes into the mouth, or sounds like it