sadhu [saadhu]: (exclamation) "It is well"; good, excellent or auspicious. It is an expression showing appreciation or agreement.
Examples of the word’s use are: ‘It is sadhu to see noble ones’ (D.I,88), ‘It is sadhu to control the mind’ (Dhp.35), and ‘Even one who leads a sadhu life will decline by consorting with a lazy person’ (It.71). Sadhu is also occasionally used in the Tipitaka as an exclamation. To show his appreciation of something Sariputta had said the Buddha responded: Sadhu, sadhu Sariputta! (Vin.I,56). Today it is common for people in Buddhist countries to say sadhu three times to express their happiness or approval of something related to the Dhamma.