- (chemistry, historical) Oxygen gas, as originally thought to be air deprived of phlogiston.
- 1775, Joseph Priestley, Experiments and Observations on Different Kinds of Air:
- My reader will not wonder, that, after having ascertained the superior goodness of dephlogisticated air by mice living in it, and the other tests above mentioned, I should have the curiosity to taste it myself.
- 2002, Philip Ball, The Elements: A Very Short Introduction, Oxford 2004, p. 30:
- Priestley never swayed from his firm conviction in the phlogiston theory as long as he lived, and he called his new gas ‘dephlogisticated air’.