அரசன்
Tamil has more words for king than it has dynasties of king. The thesaurus is genuinely full, and each word does specific work.
கோ (kō) is the deepest. It names sovereignty itself, the office that holds, before it names anyone who holds the office. It is Proto-Dravidian, native to Tamil, present in Sangam as a king-title and surviving in compounds: கோபுரம் (kōpuram, the king’s tower, now the temple gateway), கோயில் (kōyil, the king’s house, now the temple), and in king’s names — the addressee of Puṟanāṉūṟu 11 is Cēramāṉ Pālai-pāṭiya Peruṅkaṭuṅ-Kō, the great-fierce-Kō who sang of the desert.
வேந்தன் (vēntaṉ) is the imperial title. The Tolkāppiyam reserves it for the paramount kings of the three crowned dynasties — Cēra, Cōḻa, Pāṇṭiya — and distinguishes them from வேளிர் (vēḷir), the lesser chieftains. மன்னன் (maṉṉaṉ) is the office-holder, the king as ruler, less rank-specific than வேந்தன். These three native Tamil king-words coexisted in Sangam puṟam, each with its own register.
இறை (iṟai) and ஆண்டவன் (āṇṭavaṉ) were also king-words in the older Tamil thesaurus. Both have now drifted upward. இறை has become a word for the divine — the Sangam poet Iraiyanar (Iṟaiyaṉār)‘s name literally means “the Lord”, and is a common name of Shiva. ஆண்டவன் became the standard Tamil word for Lord/God in both Christian and Hindu devotional contexts. The political register emptied and the divine register filled.
அரசன் (aracaṉ) arrived through Sanskrit rājan. The borrowing is old — by Old Tamil it had been domesticated into Proto-South Dravidian *aracan, with the Dravidian-characteristic a- prefix added to satisfy phonological constraints against initial r-. The same Sanskrit word entered Tamil again later as the doublet pair ராஜா (rājā) / ராஜன் (rājaṉ), closer to the original form, likely via Prakrit. Today அரசன் is the unmarked everyday word. It has no register weight — neither archaic like கோ nor imperial like வேந்தன், neither divine like இறை nor devotional like ஆண்டவன். It is just king. This is precisely why it won.
The pattern across the entry is the upward drift. The words a culture uses for its local sovereign tend, over centuries, to become its words for the god. The Tamil king-and-god vocabulary makes this drift visible. Where the political form thinned out, the words did not vanish — they migrated to the only sovereign that remained.
Etymology phylogeny
Time runs left to right. Solid lines mark descent; dashed lines mark semantic borrowing.