bookworm

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. One who spends much time reading or studying.
2. n. Any of various insects, especially booklice and silverfish, that infest books and feed on the paste in the bindings.

Century Dictionary and Cyclopedia

1. n. A name given to the larvæ of various insects, which gnaw and injure books, but particularly to those of two species of small beetles, Anobium (Sitodrepa) paniceum and Ptinus brunneus, belonging to the family Ptinidæ. They infest old, unused books, working chiefly in the leather binding, but also riddling the leaves with small holes. The larvæ of both species are closely similar, being cylindrical and curved like those of snout-beetles, but furnished with well-developed legs, and with rather long, sparse pubescence. In the imago state, however, the species are readily distinguished, P. brunneus being much more slender in every respect than A. paniceum.
2. n. A person closely addicted to study; one devoted to the reading of or to research in books: as, “these poring book-worms,” Tatler, No. 278.

Wiktionary

1. n. Any of various insects that infest books.
2. n. An avid book reader.

GNU Webster's 1913

1. n. (Zoöl.) Any larva of a beetle or moth, which is injurious to books. Many species are known.
2. n. A student closely attached to books or addicted to study; a reader without appreciation.

WordNet 3.0

1. n. a person who pays more attention to formal rules and book learning than they merit
2. n. someone who spends a great deal of time reading