The term 'OLD ROMAN DEITY' can be summarized by the crossword solution 'DEUS', which is a Latin word meaning 'GOD'. This term refers to the gods and goddesses of the ancient Roman religion, which was practiced in the city of Rome and its surrounding areas from the 8th century BC until the 4th century AD. These deities were believed to have control over various aspects of life, such as war, agriculture, and fertility.