neur

The root neur comes from Greek neuron, which originally meant "sinew, tendon, string" — the tough fibers that tie a body together and let it move. As Greek and later medical thinking advanced, the same word came to name the body's other kind of "string": the nerve, the fiber that carries signals. English borrowed neur/neuro- almost entirely through medicine and science, so unlike Latin roots that scatter into everyday verbs, this one stays inside one clear territory — the nervous system and the mind that rides on it.

The family is remarkably regular. Add the right suffix and you get the whole anatomy of the field:

- neuron = the nerve cell itself, the basic unit.
- -logy (study of) + neuron → neurology: the medical study of nerves.
- -osis (condition) + neur → neurosis: a nerve condition — historically an emotional disorder once blamed on the nerves.
- -otic (adjective form of -osis) → neurotic: describing someone in that anxious, nervy state.
- neuro- + transmitter → neurotransmitter: the chemical that sends a signal across the gap between nerve cells.
- neur + -algia (pain) → neuralgia: pain running along a nerve.

Notice the pattern: neur names the nerve, and the suffix tells you what about the nerve — its cell (neuron), its study (neurology), its disorder (neurosis/neurotic), its pain (neuralgia), or its chemistry (neurotransmitter).

One member sits slightly outside the Greek line. enervate (to weaken, to drain of strength) comes not from Greek neuron but from Latin nervus — and nervus and neuron are the same ancient word, cognates meaning "sinew/nerve." Latin e- (out) + nervus (sinew) literally means "to cut the sinews out of" something. Pull out the tendons and the body goes limp — so enervate means to sap the strength and energy from someone. (English speakers often misread it as "to energize" because it looks like energy; it means the opposite.) So the modern split is just a spelling accident of two roads out of the same root: the Greek neur- words and the lone Latin nerv- survivor.