Top Definition
(re-ak-tent) n. 1: A substance that enters into and is altered in the course of a chemical reaction. 2: The starting material in a chemical reaction.
Power Reactant Storage Assemblies are sets of oxygen and hydrogen tanks that provide reactants for electrical power generation and basic life support to the shuttle crew.
by J. Kissling January 22, 2006

Free Daily Email

Type your email address below to get our free Urban Word of the Day every morning!

Emails are sent from We'll never spam you.