con‧vec‧tion /kənˈvekʃ
ən/ 
 noun [uncountable] technical[
Date: 1800-1900; 
Language: Late Latin; 
Origin: convectio, from Latin convehere 'to bring together', from com- ( ⇒ COM-) + vehere 'to carry']
 the movement in a gas or liquid caused by warm gas or liquid rising, and cold gas or liquid sinking 
 [TahlilGaran] Dictionary of Contemporary English ▲