Wiktionary
n. A particular breathing technique: it includes inhale via the nose while pushing air, that was stored in the cheeks, out through the lips, so allows for continuous playing of a wind instrument.
Wikipedia
Circular Breathing is the second EP released by Australian singer-songwriter Kate Miller-Heidke. It was her first to be released with a major music company, Sony BMG.
Usage examples of "circular breathing".
There is a way of playing certain musical instruments that is called 'circular breathing', devised to allow people to play the didgeridoo or the bagpipes without actually imploding or being sucked down the tube.
Her circular breathing, the special technique that allows breath in through the nose while the mouth continues to expel air through the instrument, enabled her to indefinitely sustain the sounds.