Definition of "washer"

washer¹

/ˈwɒʃə(ɹ)/

noun
plural washers
1. Something that washes; especially an appliance such as a washing machine or dishwasher.
  Quotations
  A £1.2 million carriage washer has opened at Norwich Crown Point, enabling Greater Anglia to clean its 58 Stadler trains. It is one of two new washers (the other is for '720s' at Southend), […]
  2021 January 13, “GA opens new carriage washers”, in RAIL, issue 922, page 15
2. A person who washes (especially clothes) for a living; a washerman or washerwoman.
3. A person who washes his or her hands compulsively, as a symptom of obsessive-compulsive disorder.
4. A face cloth.

washer²

/ˈwɒʃə(ɹ)/

noun
plural washers
1. A flat disk, placed beneath a nut or at some joint, to distribute pressure, alleviate friction, provide directionally differentiated friction (e.g. making the nut turn counter-clockwise only with difficulty), or prevent leakage.
verb
third-person singular simple present washers, present participle washering, simple past and past participle washered
1. (transitive) To fit (a mechanical device) with a washer.