noun
seventh anniversary of a death
Buddhist memorial service held on the seventh anniversary of a person's death. Also refers to the anniversary itself.
来月は祖母の七年忌なので、親戚が集まる予定です。
Next month is the seventh anniversary of my grandmother's death, so relatives plan to gather.
Second anniversary (counted as the third memorial service), while 七年忌 is much later.
Compound of 七 (seven), 年 (year), and 忌 (mourning, anniversary). The reading しちねんき follows standard on'yomi.