Enter a clue or pattern or both:
The Clue
Necessity: Abbr. (3 letter answer)
The Answer
REQ
Tags
Notes
The answer REQ is seen occasionally, appearing about once every 750 puzzles.
Related Clues
Necessary: Abbr.
Need: Abbr.
Not opt.
Off. order
Petition: Abbr.
R.S.V.P., for instance
Course list abbr.
Mandatory coll. course
Not an elective: Abbr.
Not elective: Abbr.
Not optional: Abbr.
Abbr. in some class descriptions
Like some univ. courses
Must-take coll. course