Chindadripet - Chinna Thari Pettai - due to the settlement of large number of weavers from kanchipuram and patnoor (pattu nool traders of saurashtra origin) people.
Mandaiveli - A place for the cattles to graze, nearby was the big town of mylapore and people would have used the river banks of adyar near mandaiveli for cattle grazing
Royapettah, Royapuram - May be short forms of Rayar Pettai, Rayar Puram named after any rayar kings/ nayaka nobles
Do you know that egmore is actually ezhumur ( not ezhumbur) Ayanavaram, Puzhal, Ambattur, Puliyoor, Padi had the same name even 1000 years before. ( i think even avadi had the same name. to check) Of courese Thiruvallikeni, mylapore and Thiruvotriyur have the anme from 6th AD.
I think AVADI is an accronym....its something like 'Armoured Vehicles and Artelery Depot of India' (???) or something... Its hardly a 100 or so years old name....I think.
The Avadi weiki mentions this armoured vehicle stuff.
But once i searched net for villages in each kottams. There i saw avadi. Ambattur is in both Thirumullai vayil and Padi epigraphs. Avadi i saw there for the first time.
pulianthope may b a old name meaning it is a grove of tamarind trees. otteri is kind of lake name we have a canal by the name called otteri nullah now, also the large lake in puzhal is called retteri meaning two lakes, this otteri is within 10 km radius so it may signify a single lake