Tam: கோயம்புத்தூர் kōyamputtūr
‘Kovan’s New City’ [Kovai] City/District, Tamil Nadu
From Kovan; Tam: putu, ‘new’; and ūr, ‘village’, ‘town’.
In this derivation Kovan puthur (named after the 9thC Irula tribal chieftain Kovan or Koyan) became Koyambatoor and was then anglicised to Coimbatore. Kovan, so they say, built canals and reservoirs so his people could take up farming.
Others suggest there is a goddess with a related story lurking in the name:
When the tract now occupied by the town of Coimbatore was forest land, inhabited by aboriginal hill-tribes, Koyan dwelt there and worshipped a goddess called Koyanamma. The name was gradually changed, first into Kovaiamma, and then into Koniamma…Gradually a flourishing town grew up, and Koniamma was adopted as one of the deities of the new colony. Centuries afterwards, Tippu Sultan, the Tiger of Mysore, when he passed by the town during one of his marches, broke down the image and demolished the temple. The glory of persecution greatly increased the fame of the goddess. The head, which had been broken off the image, was brought back to the town, a new temple built, and in a few years the goddess became very popular over the whole district’
[Whitehead (1921) p121-2].
The modern city, the second largest in Tamil Nadu, is famous for its cotton mills (it has nearly 150 of them) and the officially recognised Coimbatore Wet Grinder for making batter for dosas and idlis from rice grain.