“Microwave” is sometimes jocularly defined as “micro wave.” “When a small child gives a goodbye hand gesture, I like to call it a microwave” was posted on Twitter by Tyler Tarver Ed.S. on May 11, 2021. “Microwave: (n) A minuscule hand gesture or greeting” was posted on Twitter by Vito Cerabona on July 20, 2011.
       
”microwave (n) A hand gesture used by a midget to say hello” added to the Urban Dictionary on August 2, 2011.
     
         
Wikipedia: Microwave oven
A microwave oven (commonly referred to as a microwave) is an electric oven that heats and cooks food by exposing it to electromagnetic radiation in the microwave frequency range. This induces polar molecules in the food to rotate and produce thermal energy in a process known as dielectric heating. Microwave ovens heat foods quickly and efficiently because excitation is fairly uniform in the outer 25–38 mm (1–1.5 inches) of a homogeneous, high water content food item.
 
Twitter
Tyler Tarver Ed.S.
@tylertarver
When a small child gives a goodbye hand gesture, I like to call it a microwave.
9:53 AM · May 11, 2011·Echofon
   
Twitter
Vito Cerabona
@Vito_C_
Microwave: (n) A minuscule hand gesture or greeting.  #ued
10:44 AM · Jul 20, 2011·Twitter for Mac
     
Urban Dictionary 
microwave
(n) A hand gesture used by a midget to say hello
Hey, the midget over there just gave me a microwave
by Johhny Bravo August 02, 2011
 
Twitter
Danny Innes
@DannyInnes80
@JoshKads @BossAmo8 @JWynter_95\
What’s a microwave?
Is a small hand gesture a midget makes…
5:48 AM · Aug 3, 2011·Twitter for iPhone
   
Twitter
Tireworld99
@tireworld99
Definition of MICROWAVE - “A hand gesture used by a midget to say hello..”
11:35 AM · Aug 4, 2011·Twitter Web Client
   
Twitter
Suyi
@Suyi
microwave - A hand gesture used by a midget to say hello (urban dictionary)
11:44 AM · Aug 4, 2011·Twitter Web Client
 
Twitter
Men’s Humor
@MensHumor
Microwave: (noun) A hand gesture used by a midget to say hello.
8:00 PM · Aug 26, 2011·Hootsuite
   
Twitter
milk
@miilkkk
Microwave: (noun) A hand gesture used by a midget to say hello.
5:15 PM · Nov 17, 2011·Twitter Web Client
 
Twitter
Urban Dictionary
@urbandictionary
@Glenntertain: microwave: (n) A hand gesture used by a midget to say hello http://microwave.urbanup.com/5992504
12:53 PM · Sep 6, 2012·erased2906781
 
Twitter
Condescending Wonka
@OhWonka
Microwave: (noun) A hand gesture used by a midget to say hello.
12:11 PM · Sep 26, 2012·Buffer
   
Twitter
The Cultured Ruffian
@CulturedRuffian
MICROWAVE: A hand gesture used by the tiny man-hands of Donald Trump to say hello or goodbye.
4:11 PM · Feb 11, 2018·Twitter for Android
 
Twitter
Chrystal Alexandroff
@chrystalex1
Microwave (n.) A hand gesture used by a midget to say hello.
11:10 PM · Apr 28, 2021·Twitterrific for iOS