ἄνοδος

If current flows down (cathode), it must flow up somewhere. Whewell's logic was geometric and Greek. Anodos meant 'the way up'—ana (up) plus hodos (way). In the same 1834 correspondence where he proposed cathode, he proposed anode as its opposite.

Both words worked because they were transparent. A scientist reading cathode immediately understood: the way down. A scientist reading anode immediately understood: the way up. The names encoded their meaning in the language of ancient Greece, borrowed from a civilization two thousand years gone.

Whewell and Faraday were inventing language for phenomena no ancient Greek ever witnessed. Yet Greek provided the metaphor—paths, directions, flows—because Greek had always been used for naming invisible things. Medicine, rhetoric, philosophy: Greek had words for thinking about what you cannot touch.

Anode and cathode remain paired in every physics textbook. Neither makes sense without the other. Whewell's naming was balanced, binary, complete. The vocabulary problem was solved in a single act of etymological engineering.