object language

Short definition from Wiktionary

Noun

1. 1
   A language or a part of a language that is used to speak about objects but not about sentences or propositions.
2. 2
   the language of the headwords in a dictionary (in a French-to-English translation dictionary, French is the object language)
3. 3
   target language; the language of the object code, the output of a compiler (not necessarily executable machine code)