Rebreather

Part of speech: noun

Definitions

1. A device that allows a person to breathe underwater by recycling exhaled gas after removing carbon dioxide and replenishing oxygen; used primarily in diving and submerged activities to extend underwater time
2. An apparatus designed to recycle the air a diver exhales by scrubbing carbon dioxide and adding oxygen, enabling longer submersion without releasing bubbles; commonly employed in underwater exploration
3. Equipment that supports prolonged breathing underwater by reprocessing the exhaled breath, eliminating carbon dioxide, and reintroducing oxygen to the breathing circuit; essential for deep or stealth diving operations

Etymology: "Rebreather" is about as transparent as English compounds get: it is the verb "rebreathe," meaning to breathe again the same air that has already been exhaled, with the agent suffix "-er" attached to name the device that does this. The pattern is the same one found in "toaster" or "cooker," where a machine is named for the action it performs. The prefix "re-" carries its familiar sense of repetition, so the word describes air being taken back in rather than fresh air drawn from outside. The device is named for its function rather than for any inventor or event. Divers and miners needed equipment that recycled breath, and the name simply says what the apparatus does. Its meaning has stayed fixed since the word was formed, so there is no older sense to recover.

Synonyms: scuba apparatus, closed-circuit breathing apparatus, oxygen rebreather, breathing apparatus

Antonyms: open-circuit scuba, snorkel