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cat·a·lyst

(kătl-ĭst)

1. Chemistry A substance, usually used in small amounts relative to the reactants, that modifies and increases the rate of a reaction without being consumed in the process.

2. One that precipitates a process or event, especially without being involved in or changed by the consequences: "A free press ... has remained ... a vital catalyst to an informed and responsible electorate" (Robert O'Neal).

[From CATALYSIS.]

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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