English suffix ~ER
*In English we often use the suffix ~er after a verb to show that a person or thing does that verb.
In baseball the person who pitches the ball is called the pitcher, the person who catches the pitches is called the catcher.
A floor wiper wipes your floor.
A sharpener makes your pencils sharp. (It sharpens your pencils)
A container contains - holds - something. Tupperware is a well known company in North America that makes plastic containers.