What is the word describing renaming an event or process with a symbolic phrase or word?

For example, in an aerospace business setting we are trying to find a title for the process to get approval for a new good or service. We are suggesting names like: green light, take off, launch pad, etc...

What are these names called? Is there a word for it? They are not euphemisms because we're not referring to something unpleasant or embarrassing. It's not stenography because we're not trying to hide anything.

Usage example: I don't like "green light" as a (word) because it's too vague. I think a better (word) would be "take off".

I'm thinking maybe jargon is the right word for it. It would not be industry-specific or even company-specific jargon. I think the phrase I'm looking to identify with the word would be department specific.

An idiom is a set phrase that has acquired a meaning separate from the combined meaning of the individual words. A metaphor is figurative language in which an analogy is implicitly given.

Those names (symbolic words or phrases) are terms specific to the respective field and the technical term (mass noun) for them is terminology, sometimes also referred to as nomenclature or jargon.

ODO:

terminology NOUN [mass noun] The body of terms used with a particular technical application in a subject of study, profession, etc.

‘I realise that the army's history and terminology is an unknown jungle to many.’

nomenclature

NOUN [mass noun]
1.1 The body or system of names used in a particular specialist field. ‘the students found it hard to decipher the nomenclature of chemical compounds’

1.2 [formal] The term or terms applied to someone or something. ‘‘customers’ was preferred to the original nomenclature ‘passengers’’

jargon
NOUN [mass noun]
1 Special words or expressions used by a profession or group that are difficult for others to understand.

‘legal jargon’