1A relation or connection — indicating that two or more things are linked, share a common factor, or affect one another; can be used as a verb with 'suru.'
この事故と天候の関連を調べている。
They are investigating the connection between this accident and the weather.
関連する資料をすべて集めてください。
Please gather all the related documents.
睡眠不足と集中力の低下には関連があると言われている。
It is said that there is a connection between lack of sleep and decreased concentration.
その二つの事件に関連は見られなかった。
No connection was found between the two incidents.