Garum, similar to liquamen, was a type of fermented fish sauce

Fish sauce

Fish sauce is a condiment that is derived from fish that have been allowed to ferment. It is an essential ingredient in many curries and sauces. Fish sauce is a staple ingredient in numerous cultures in Southeast Asia and the coastal regions of East Asia, and features heavily in Thai and Vietnamese...

 condiment that was an essential flavour in Ancient Roman

Ancient Rome

Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....

 cooking, the supreme condiment

Condiment

A condiment is an edible substance, such as sauce or seasoning, added to food to impart a particular flavor, enhance its flavor, or in some cultures, to complement the dish. Many condiments are available packaged in single-serving sachets , like mustard or ketchup, particularly when supplied with...

.

Although it enjoyed its greatest popularity in the Roman world, it originally came from the Greeks

Ancient Greece

Ancient Greece is a civilization belonging to a period of Greek history that lasted from the Archaic period of the 8th to 6th centuries BC to the end of antiquity. Immediately following this period was the beginning of the Early Middle Ages and the Byzantine era. Included in Ancient Greece is the...

, gaining its name from the Greek

Greek language

Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 words garos or garon (γάρον), which named the fish whose intestines were originally used in the condiment's production.
For the Romans it was both a staple to the common diet and a luxury for the wealthy.