There are 24 basic mudras or hand signs mentioned in the classical Indian text on Kerala dance, Hasthalakshanadeepika. These Mudras are used in the classical dance dramas of Kerala, like Kathakali, Kutiyattam, Nangiarkoothu, Mohiniyattam and Ottanthullal.

Keeping the index finger straight, the thumb stretching sideways and the other three fingers slightly bent towards the palm is Ardhachandra.
Some signs shown in the Ardhachandra mode using both palms indicate :
If so, what, stupor, sky, blessing, God, memory, grass and hair of males.
One palm indicates :
Starting, smile, what and derision.