The term 'Corinthian Consonant' is a reference to the ancient Greek city of Corinth, which was known for its rich culture and art. The crossword solution for this term is PSI, which is the 23rd letter of the Greek alphabet. It is pronounced 'SIGH' and is often used in mathematics and science to represent various concepts. PSI is also used in the English language to represent the sound of a hissing snake.