Source: The Collaborative International Dictionary of English v.0.48
Trilingual \Tri*lin"gual\, a. [L. trilinguis; tri- (see Tri-)
+ lingua tongue, language. See Lingual.]
Containing, or consisting of, three languages; expressed in
three languages.
[1913 Webster]
The much-noted Rosetta stone . . . bears upon its
surface a trilingual inscription. --I. Taylor.
[1913 Webster]