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prefrontal lobotomy

A lobotomy in which the white fibers that connect the thalamus to the prefrontal and frontal lobes of the brain are severed, formerly performed to treat behavior that was considered to be abnormal.

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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