In general, volatile (from the Latin "volatilis" meaning "to fly")is an adjective used to describe something unstable or changeable.
Volatile memory is computer storage that only m...(WhatIs.com)
How to disable non-volatile caching in Windows Vista
In this excerpt from Chapter 31 of the book "Windows...(SearchEnterpriseDesktop.com)
Volatile memory contrasts with nonvolatile memory , memory that does not lose content when power is lost, that has a continuous source of power, or does not need to have its memory content periodically refreshed.