I have a propensity for collecting old (classic?) engineering reference texts, and nabbed this one at the very beginning of my utility career. It's a 1977 copy of the Edison Electric Institute's Glossary of Electric Utility Terms, and it almost feels like a set of mimeographed pages stapled together in pamphlet format. It might even have been created on an IBM Selectric typewriter!
In any event, the terms and definitions are still pretty current, and you could develop a pretty good quiz to determine how deep a utility employee's experience is. For example, there are nine different definitions for demand and thirteen for electric energy.
Many of the definitions are clearly based on federal regulatory reporting requirements, and others are related to financial reporting specific to the utility industry.
EEI does maintain a current, on-line version of the Glossary, but unfortunately, it is behind a member pay wall.