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bi·o·film

(bīō-fĭlm′)

A complex structure adhering to surfaces that are regularly in contact with water, consisting of colonies of bacteria that secrete a mucilaginous protective coating in which they are encased. Biofilms, which are resistant to antibiotics and disinfectants, corrode pipes and cause diseases such as lung infections, but they can be used beneficially to treat sewage, industrial waste, and contaminated soil.

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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