In computer memory it means that power is not required for the data to remain in the circuit. In physics is means that the substance does not evaporate.
Non-volatile
ROM is non-volatile memory.
In chemistry, we use the term volatile to speak to the ability of a substance to become a vapor, or to vaporize. There are many non-volatile compounds. Common table salt, NaCl, won't be encountered as a vapor in any "normal" situation. You can't even get salt to vaporize in a kitchen oven set on high. There are many, many other non-volatile compounds about.
volatile will evaporate
volatile will evaporate
DRAM is a volatile memory
DRAM is a volatile memory
RAM is volatile storage, short-term storage or working memory. As opposed to a hard-drive which is non-volatile, long term storage or a mass-storage medium.
non volatile memory is memory that doesn't wipe after the computer shuts down e.g: Flash memory.
DRAM is volatile.
waste and recycling
The PlayStation 2 memory cards have the non-volatile and not the volatile flash memory.