It was originally used to sing in harmony, now used in many ways but primarily in the 104th Division Army Band as an affirmative, an adjective, a greeting, a noun, an ice breaker, an awkward silence filler, a verb, an agreement, etc. Yeow can pretty much be used to write a novel. It is most often included with a hand gesture where one has the index finger swooped upward and inward with a sharp wrist flick . In times with an injury, yeow can also be used with a cane.
"How did that sound?"