noun
interment of ashes ceremony; ash interment rite
A Buddhist or secular ceremony where cremated remains are placed into a grave or columbarium. Often held after the funeral and cremation.
納骨式は火葬の後、四十九日に行われることが多い。
The ash interment ceremony is often held on the 49th day after cremation.
火葬 is cremation, which precedes the 納骨式.
Compound of 納骨 (のうこつ, 'interment of ashes') and 式 (しき, 'ceremony').