Meaning of Library of Congress classification

Li'brary of Con'gress classifica"tion

Pronunciation: [key]
— Library Science. Library Science.
  1. a system for classifying books and other materials, using for its notation both letters and numerals to allow for expansion: originally developed at the Library of Congress for classifying its books and subsequently adopted by other libraries.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.