Arudi
A marked point of emphasis or repose within a musical phrase.
In a ragam–tanam–pallavi, arudi usually refers to the prominent resting or accent point that articulates the pallavi line. The words, melody and rhythm bring attention to that point.
Arudi and Graha
Graha tells you where the line begins relative to the tala. Arudi tells you where an important internal emphasis falls. A line can begin after the first count and reach its arudi later in the cycle.
The word also occurs in discussions of cadences and rhythmic resolutions; its precise use depends on the musical context.