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pis·ton

(pĭstən)

1. A solid cylinder or disk that fits snugly into a larger cylinder and moves under fluid pressure, as in a reciprocating engine, or displaces or compresses fluids, as in pumps and compressors.

2. Music A valve mechanism in brass instruments for altering the pitch.

[French, from Italian pistone, pestone, large pestle, from pestare, to pound, crush, from Late Latin pistāre, frequentative of Latin pīnsere, pīnsāre.]

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piston

in an internal-combustion engine

Indo-European & Semitic Roots Appendices

Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

Indo-European Roots

Semitic Roots

The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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