Origin: Latin prefix inter-
Interlingua has 3 different meanings across 2 categories:
an artificial language proposed for use as an auxiliary international language; based on words common to English and the Romance languages
an interlanguage
An interlanguage based on Romance languages, English, German, Russian and Latin, developed by the International Auxiliary Language Association, and first published in 1951.
The term likely originated independently in several languages, though its modern usage stems from the Interlingua word itself. It is formed from the Latin words inter, meaning "between," and lingua, meaning "language."