footnote
noun uk/ˈfʊt.nəʊt/ us/ˈfʊt.noʊt/
[ C ]脚注
a note printed at the bottom of a page that gives extra information about something that has been written on that page
[ C usually singular ]无足轻重的事件（或问题、细节）
an event, subject, or detail that is not important
His tumultuous triumph five years ago now seems like little more than a footnote in history. 他5年前名噪一时的大胜利现在看来仿佛只是历史上一个无关痛痒的小插曲。