From Longman Dictionary of Contemporary Englishmicrowavemi‧cro‧wave1 /ˈmaɪkrəweɪv/ ●●● S2 noun [countable] 1 
(also microwave oven) a type of oven that cooks food very quickly using very short electric waves instead of heat I’ll heat it up in the microwave.2 TPEa very short electric wave that is used in cooking food and sending messages by radio, and in radar
(also microwave oven) a type of oven that cooks food very quickly using very short electric waves instead of heat I’ll heat it up in the microwave.2 TPEa very short electric wave that is used in cooking food and sending messages by radio, and in radarExamples from the Corpus
microwave• Compact models are about the size of a microwave.• With a microwave, he calculates, we could get rid of our cook.• If this would otherwise be done leaving food out or in the refrigerator, then the microwave actually adds to energy use.microwavemicrowave2 verb [transitive] DFCDFUto cook something in a microwave oven You can heat it up under the grill or microwave it.► see thesaurus at cook —microwaveable, microwavable adjective a new range of microwavable snacks→ See Verb tableExamples from the Corpus
microwave• This involved grating soap, microwaving it and finally putting it through a food processor. 