Which of the following refers to specialized terminology used by professionals in a specific field?

The term that refers to specialized terminology used by professionals in a specific field is "jargon." Jargon consists of words or phrases that are unique to a particular profession or area of expertise, making communication more efficient within that context. For example, in the travel industry, terms like "FIT" (Free Independent Traveler) or "GDS" (Global Distribution System) are considered jargon because they have specific meanings that may not be readily understood by outsiders.

Slang, in contrast, refers to informal or colloquial language that may be used in casual conversations and can vary significantly across different regions and social groups. Dialect relates to variations in language that are specific to particular geographic areas or social classes, often involving differences in pronunciation, vocabulary, or grammar. Language, in a broader sense, refers to any system of communication, encompassing both everyday words and specialized terminology but not limited to the professional context.

Thus, jargon is the most precise term for the specialized terminology used by professionals in a specific field.