Definition of "soundproof" [soundproof]

• Not penetrable by audible sound. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Sunday Book Review cover: Walter Kirn on How Fiction Works by James Wood: The heroes of this great artistic labor tend to be semimonastic intro­verts who, like Wood’s beloved Henry James and Gustave Flaubert, toil with the doors shut and locked, in soundproof splendid isolation, attentive to the subtle frictions among nouns and adjectival phrases ...."
• "Traditionally, “public places” refer to any regions in a community freely accessible to members of that community; “private places” refer to soundproof regions where only members or invitees gather—the traditional concern for public order beginning only at the point where a private gathering begins to obtrude upon the neighbors."
• "The Reading Rights Coalition is fighting efforts to "soundproof" eBooks, and so are these individuals who have signed petition against this practice."