means The scientific study of the nervous system — how brains and nerves are built, how they fire, and how they give rise to thought, sensation, and behavior.

from A modern compound, stitched from Greek 'neuron' — originally 'sinew' or 'string,' the word ancient anatomists used before they understood nerves as something distinct — joined to 'science,' from Latin 'scientia,' knowledge. The discipline crystallized under that name in the mid-20th century, when fields that had drifted apart — anatomy, physiology, psychology — were gathered back under one roof to study the nervous system as a whole.