noun, noun or participle which takes 'suru'
studying two lessons
Refers to the act of studying two lessons, often in a textbook or course context. Can be used as a noun or with する.
今日は二課勉強する予定です。
I plan to study two lessons today.
二課勉強は大変だった。
Studying two lessons was tough.
Compound of 二課 (two lessons) and 勉強 (study). The exact derivation is straightforward; no historical uncertainty.