n. Compensation for services that do not have a predetermined value.
the GNU version of the Collaborative International Dictionary of English
n. A fee offered to professional men for their services.
n. An honorary payment, usually in recognition of services for which it is not usual or not lawful to assign a fixed business price.
The Century Dictionary and Cyclopedia
n. A fee for services rendered, especially by a physician or other professional person.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a fee paid for a nominally free service
Word Usage
"But always before he reached the middle he struck for what they called his honorarium; and this troubled them, for the tale was appearing week by week as it was written."