What term refers to the specialized language used in an occupation or interest group?

The term "jargon" specifically refers to the specialized language or terminology that is used within particular professions or interest groups. This language is often characterized by the use of unique words or phrases that may not be easily understood by outsiders. Jargon serves various purposes, such as facilitating precise communication among members of a specific field, conveying specialized meanings, and establishing a sense of identity within the group.

While "slang" might refer to informal, colloquial language that often develops within social groups, it is broader and not necessarily tied to a specific profession or technical field. "Metaphor" and "oxymoron" are literary devices; a metaphor describes one thing in terms of another, while an oxymoron combines contradictory terms. These terms do not pertain to language used in a specific occupational context. Thus, "jargon" is the most fitting choice as it captures the essence of specialized language used in particular fields and communities.