Slang consists of words used only by specific social groups, such as teenagers or soldiers.
Idioms are a group of words that seem to have a meaning that you can’t deduce easily from those around them. The words in an idiom have meanings on their own, but together they have a completely different meaning.
A colloquialism is any word or phrase that is not formal, in other words, one that is usually used in casual conversation.
People in IT tend to have their own sublanguage that, for the most part, the people we work with understand. ...