v. To hear something that wasn't meant for one's ears.
the GNU version of the Collaborative International Dictionary of English
v. To hear more of (anything) than was intended to be heard; to hear by accident or artifice.
v. To hear again.
The Century Dictionary and Cyclopedia
To hear (one who does not wish to be heard or does not know that he is heard, or what is not addressed to the hearer or is not intended to be heard by him); hear by accident or stratagem.
To hear over again; hear from beginning to end.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
v. hear, usually without the knowledge of the speakers
Word Usage
"How charmed I am when I overhear a German word which"