bibliophile; book lover
Refers to a person who loves books, often as a collector or avid reader. Slightly formal or literary tone.
彼は有名な愛書家で、自宅に何千冊もの本を所蔵している。
He is a well-known bibliophile and owns thousands of books at home.
Compound of 愛 (love) + 書 (books) + 家 (person). The exact historical derivation is uncertain, but the word follows a common pattern for naming enthusiasts.