classroom
n.a room in a school or college where students have lessons. It usually contains desks, chairs, and a board for the teacher to write on.
n.a room in an educational institution where teaching and learning activities take place.
“The students are sitting in the classroom.”
“Our teacher decorated the classroom with colorful posters to make the learning environment more welcoming.”
“Modern classroom design often emphasizes flexible seating arrangements to encourage collaboration among students during group projects.”
Often used without an article after the preposition 'in' when referring to the activity of learning (e.g., 'learning in the classroom').
Usage classroom instruction
From class + room.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.