Englishfor English speakers
cation
Noun
—
A cation is a positively charged ion.
exchange
Verb
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Two people exchange two things when each person gives a thing to the other person. They can exchange two things, or they can exchange a thing for money.
The children can exchange toys so that each child has a new toy to play with.
exchange
Noun
—
An exchange is the act of exchanging.
I did well in that exchange. Now I have three good new books, and I only paid a little money.
filter
Noun
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A filter is a piece of equipment that put gas or liquid through to take out the parts you don't want, to clean it.
Car engines have a fuel filter to keep the fuel clean.
filter
Verb
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If you filter a gas or a liquid, you put it through something that takes out the parts you don't want.
We filter the water.