Answer:
Jargon is a term used to express ideas related to a particular trade.
Step-by-step explanation:
Let's define each term:
Colloquialism- the use of ordinary words or phrases
Idiom- a group of words that do not have a literal meaning, but the meaning is understood (example: it's raining cat's and dogs)
Jargon- Words that are used in a particular profession and are difficult for others to understand (legal jargon, medical jargon)
Slang- very informal words
Based on these definitions, it is easy to see that jargon is the term used to express ideas related to a particular trade, like law or medicine.