The most popular explanation that is given to the word telugu is that it comes from the word trilinga, i.e. from the three temples at Srisailam, Drakasharamam, and Kaleshwaram. However, not many scholars accept this view. Let us examine some of them here.
Which of the two words is older? telugu or tenugu ? Some say that tenugu is older than telugu because Nannaya used the word tenugu and Ketana who is younger than Nannaya used the word telugu in his Andhra Bhaashaa Bhushanam. Malliya Raechana wrote a grammar book (Lakshana Granthamu) called Kavi Janaashrayamu. But he didn't use this word in the place of 'praasa' anywhere, so we are not sure what he really used.
The popular notion is that the first person to use the word trilinga is Vidyanaatha in Kakatiya era. Actually, the first person to use the word trilinga is Rajashekhara in Vidhdhasaala Bhanjika. He is the first person to use trilinga with a ra vattu . Markandeya and Vayu Puranas mention only tilinga. One of the oldest works in Tamil called Agattiyam says Konganam Kannadam Kollam telungam . On the whole, it is more probable that the word telugu is older than the word tenugu.