an intricate knot tied by Gordius, the king of Phrygia, and cut by the sword of Alexander the Great after he heard that whoever undid it would become ruler of Asia
any very difficult problem; insoluble in its own terms
the quality imparted to voiced speech sounds by the action of the resonating chambers of the throat and mouth and nasal cavities
a vibration of large amplitude produced by a relatively small vibration near the same frequency of vibration as the natural frequency of the resonating system
an excited state of a stable particle causing a sharp maximum in the probability of absorption of electromagnetic radiation
showing a fighting disposition; "highly competitive sales representative"; "militant in fighting for better wages for workers"; "his self-assertive and ubiquitous energy"