MEANING:\ . noun:
1. A trainee astronaut.
2. A person who behaves strangely or appears to be out of touch with reality.

ETYMOLOGY: From Robert Heinlein’s 1948 novel Space Cadet. Why the second sense of the term? The book inspired TV and radio shows and comics and the term became popular. Eventually, the meaning shifted and now a space cadet is one who is spaced out or has their mind in space, probably as a result of drug use. Earliest documented use: 1948. Other words coined by Robert Heinlein that have become words in the English language are grok and waldo.

PACE CADET - Freshman in a New York city university (it also has a campus in Westchester)

APACE CADET - energetic, bustling trainee

SPACE CARET - editors' symbol for "insert a two-en quad here"