delta

Where does the word "delta" come from? It comes from Greek delta, and was adopted directly into English (1700s).

Delta’s story begins in Greek: delta meant “the letter delta.” The fourth letter of the Greek alphabet, shaped like a triangle. It reached English by 1700s as delta. Applied to the triangular landform at a river's mouth, resembling the letter. Today, delta means a triangular area of sediment deposited at a river's mouth.

1. Stage 1 · Greek · ancient delta "the letter delta", the fourth letter of the Greek alphabet, shaped like a triangle.
2. Stage 2 · English · 1700s delta "a triangular landform at a river's mouth", applied to the triangular landform at a river's mouth, resembling the letter.