noun
independent research project; free study project
Commonly refers to a self-directed research project assigned during summer vacation in Japanese elementary and junior high schools. Students choose their own topic, investigate it, and present their findings.
夏休みの自由研究で、アリの観察をしました。
For my summer vacation independent research project, I observed ants.
自由研
I haven't decided yet what topic to choose for my free study project.