the GNU version of the Collaborative International Dictionary of English
adj. Having a valence of four; tetratomic; quadrivalent.
The Century Dictionary and Cyclopedia
Same as quadrivalent.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. haveing a valence of four
Word Usage
"Since there are four distinct dengue viruses, the challenge is to concoct a four-way, or "tetravalent," vaccine, effective against all strains at once."