Looking through the Redbox and the Bluebox I noticed that there are abilities and there are checks. But there is no cohesive concept of an “ability check”. Then I looked in Gygax’ AD&D Dungeon Masters Guide and did not find the term “ability check” there either.
I did however find the term “Ability Check” prominent and repeated often in the 1991 “Rules Cyclopedia” (ex. chapter 13).
Where in D&D published material did the term “Ability Check” first appear?