Here's how to break down the word:
* நிகழ்ச்சி (Nikaḻcci) means "event" or "program"
* நிரல் (NiraL) means "list" or "schedule"
Therefore, நிகழ்ச்சி நிரல் (Nikaḻcci NiraL) literally translates to "event list" or "program schedule," making it the closest equivalent to "Agenda" in Tamil.