# piston

/ˈpɪstən/ (US) · /pˈɪstən/ (UK)

Source: https://englishreference.com/word/piston
Updated: 2026-08-15

## Senses

### 1. engine part

noun · CEFR B2 · Technical

a metal cylinder that moves up and down inside an engine to help create power.

For teachers: a sliding piece moved by or moving against fluid pressure, typically consisting of a short cylindrical body fitting within a cylindrical chamber.

- The mechanic explained that one piston in the engine was stuck and needed repair.
- The internal combustion engine relies on the rapid movement of pistons to convert the energy from burning fuel into mechanical motion.

### 2. musical instrument valve

noun · CEFR C1 · Technical

a part of a brass instrument, like a trumpet, that you press to change the note.

For teachers: a valve mechanism in brass instruments that, when depressed, redirects air into additional tubing to alter the pitch.

- The trumpet player pressed the first piston to play a lower note.
- Unlike the slide on a trombone, the pistons on a tuba allow for rapid, precise changes between notes in complex passages.

### 3. to move like a piston

verb · CEFR C2 · Literary

to move up and down or in and out very quickly and steadily.

For teachers: to move with the rhythmic, reciprocating motion characteristic of a piston in a cylinder.

- The runner's legs continued to piston back and forth as he neared the finish line.
- The heavy machinery began to piston rhythmically, shaking the factory floor with every downward stroke.

## Examples

- The engine has four pistons moving at high speed.
- The mechanic explained that the damaged piston was preventing the engine from generating enough power to accelerate.
- In a reciprocating internal combustion engine, the piston transfers the force of expanding gas in the cylinder to the crankshaft via a connecting rod, converting thermal energy into mechanical work.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.