suc ‧ tion /ˈsʌkʃ ə n/ BrE AmE noun [uncountable]
[ Date: 1600-1700 ; Language: Late Latin ; Origin: suctio , from Latin sugere 'to suck' ]
1 . the process of removing air or liquid from an enclosed space so that another substance is sucked in, or so that two surfaces stick together:
My vacuum cleaner has very good suction.
a suction pump
2 . the force that causes a substance to be sucked into a closed space when the air or liquid already present is removed