It took 37 years by scholars at the University of Chicago to compile the dictionary.
The ancient language is Demotic Egyptian, a name given by the Greeks to denote it was the tongue of the demos, or common people.
It was written as a flowing script and was used in Egypt from about 500 BC to 500 AD, when the land was occupied and usually dominated by foreigners, including Persians, Greeks and Romans.
"Demotic was used for business and legal documents, private letters and administrative inscriptions, and literary texts, such as narratives and pieces of wisdom literature," said Janet Johnson, editor of the Chicago Demotic Dictionary and professor at the Oriental Institute of the University of Chicago.
"It was also used for religious and magical texts as well as scientific texts dealing with topics such as astronomy, mathematics and medicine.
"It is an indispensable tool for reconstructing the social, political and cultural life of ancient Egypt during a fascinating period of its history," she said.
The advent of computer technology facilitated the assembly of the Demotic Dictionary.
The language lives on today in words such as adobe, which came from the Egyptian word for brick.
The word moved through Demotic, on to Arabic and eventually to Spain during the time of Islamic domination there, said Johnson.
The dictionary is based on texts in Demotic that were published by scholars from 1955 to 1979, and lists new words.
