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pen·e·trom·e·ter

(pĕn′ĭ-trŏmĭ-tər) also pen·e·tram·e·ter (-trămĭ-tər)

1. A device for measuring the penetrating power of radiation, especially x-rays.

2. A device for measuring the penetrability of semisolids.

pen·e·tram·e·ter

(pĕn′ĭ-trămĭ-tər)

Variant of penetrometer.

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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