|Origin:||Perhaps from Middle Dutch swijch 'small thin stick'|
switch2 S3 [countable]
a piece of equipment that starts or stops the flow of electricity to a machine, light etc when you push it:
Where's the light switch?
press/flick/throw etc a switch
Tom flicked the switch, but nothing happened.
She claims she is willing to throw the switch of the electric chair.
at the flick of a switch (=very quickly and easily, by pressing a switch)
Petrol can be chosen at the flick of a switch.
a complete change from one thing to another:
an important policy switch
the switch from agriculture to dairy production
a switch in emphasis
More shoppers are making the switch to organic food.
that's a switch American English spoken informal (=used to say that someone's behaviour is different from usual)
'Ed's the only one who's not eating.' 'That's a switch!'
a piece of railway track that can be moved to allow a train to cross over from one track to another
a thin stick that bends easily