maser

noun

1. a device for the coherent amplification or generation of electromagnetic radiation (especially of microwave frequency) by the use of excitation energy in resonant atomic or molecular systems
2. Any celestial object that generates microwaves using the same method
3. (alt-of, countable, obsolete, uncountable)Obsolete spelling of mazer.
4. (abbreviation, acronym, alt-of)Acronym of microwave amplification by the stimulated emission of radiation.