noun
long period of time; many years
Literary or formal noun emphasizing an extended duration, often used in poetic or reflective contexts. Not common in everyday speech.
長日月を経て、その伝統は今も続いている。
Over a long period of time, that tradition continues even now.
彼は長日月の研究の末、ついに新発見を成し遂げた。
After many years of research, he finally made a new discovery.