Nobody Knows Why a Metal Ring Is Called a Washer
A washer washes, or is a flat ring used with a bolt. The second sense has no agreed explanation, which is unusual for such an everyday word.
A washer is a machine or person that washes — and also a flat ring placed under a bolt head to spread the load. The second sense appears in English in the 1300s and nobody has explained it convincingly. It may be unrelated to washing entirely, or may come from an idea of a ring that keeps water out. Dictionaries record it and shrug.
- A washing machine. *Put it in the washer.*
- A flat ring. *A rubber washer.*
- A person who washes. *A dish washer.*
- Washer-dryer — a combined machine. *A washer-dryer in the kitchen.*
- Tap washer — the seal in a dripping tap. *Replace the tap washer.*
Word forms
| Form | Word | Example |
|---|---|---|
| Verb | wash | Wash it out. |
| Agent | washer | A new washer. |
| Plural | washers | A packet of washers. |
| Compound | dishwasher | Load the dishwasher. |
| Compound | washer-dryer | A washer-dryer. |
- The tap drips because the washer has perished.Plumbing.
- The washer finished its cycle.Appliance.
- Fit a washer under the nut.Engineering.
What a washer actually does
- Spreads the load of a bolt head over a wider area
- Protects the surface from being marked as the bolt turns
- Spring washers resist loosening under vibration
- Sealing washers keep water or air out of a joint
- Tap washers are the rubber discs that stop a tap dripping
From *wash*, Old English *wascan*, plus the agent ending -er. The mechanical sense is recorded from the 1300s and its origin is uncertain.
Why is a metal ring called a washer?
No one knows. The sense is recorded from the 1300s and dictionaries list it as of uncertain origin.
Why does a tap drip?
Usually because the rubber washer inside has hardened or worn, so it no longer seals against the seat.