also: かたづ
The audience watched the game with bated breath.
During his presentation, the room was so quiet you could hear a pin drop.
Standard kanji spelling. The reading かたず is more common than かたづ.
Alternate reading; かたず is preferred in modern usage.
Compound of 固 (hard, stiff) and 唾 (saliva). The image is of saliva that becomes thick or hard to swallow due to nervous tension.