Here are some other, slightly less common terms:
* குமாரன் (kumaaran): This is more formal and often used in literary contexts.
* பிள்ளை (pillai): This word can mean "child" in general, but it can also specifically refer to a son.
* மகன் (makan): This is the most common and straightforward word for "son".
The appropriate term to use would depend on the context and the level of formality.