a device that ties knots in thread during the manufacture of yarn
3.
a person or thing that takes out or removes knots
Word origin
[1705–15; knot1 + -er1]This word is first recorded in the period 1705–15. Other words that entered Englishat around the same time include: condominium, costume, junction, splash, zigzag-er is a suffix used in forming nouns designating persons from the object of their occupationor labor (hatter; tiler; tinner; moonshiner), or from their place of origin or abode (Icelander; southerner; villager), or designating either persons or things from some special characteristic or circumstance(six-footer; three-master; teetotaler; fiver; tenner)