Related Clues:

• Mouth formation
• Anything triangular
• 4th Greek letter
• The fourth Greek letter
• River mouth in the Greek alphabet
• Greek letter at the mouth of the river
• Triangular river mouth
• Fourth letter of Greek alphabet
• Triangular land at mouth of river
• Triangular patch of land at mouth of river
• The fourth Greek letter found at river's mouth
• Area where a river divides before entering the sea
• The Greek D (5)
• Fourth letter of the Greek alphabet
• Big mouth may have dealt with this