Many people use the term Snake Case to describe variables or other symbols
When did this term enter into use?
A person named Jack Dahlgren claims on Quora he invented the term in 2002 when he worked at Intel.
Here's what he posted at above link:
The earliest use I found in Usenet is in a post by Gavin Kistner to comp.lang.ruby on 23rd February 2004:
Ruby still uses this term today, for example in The Ruby Style Guide: