Names :

The name Chennai is an eponym, etymologically derived from Chennapattinam or Chennapattanam, the name of the town that grew up around Fort St. George, built by the British in 1640 A.D. There are different versions about the origin of the name. When the British landed here in 1639 A.D. it was said to be part of the empire of the Raja of Chandragiri. The British named it Chennapatnam after they acquired it from Chennappa Nayaka, a Vijayanagar chieftain. Gradually, the name was shortened to Chennai. The first instance of the use of the name Chennai is said to be in a sale deed dated August 1639 to Francis Day, an agent for the British where there is a reference to Chennaipattinam.

However, some believe Chennapattinam was named after the Chenna Kesava Perumal Temple, as the word Chenni in Tamil means face, and the temple was thought of as the face of the city.

The former name, Madras, is derived from Madraspattinam, a fishing village that lay to the north of Fort St. George. The origin of the name Madraspattinam is a subject of disagreement. One theory holds that the Portuguese, who arrived in the area in the 16th century, may have named the village Madre de Deus. However, historians believe that the village's name came from the once prominent Madeiros family (variously known as Madera or Madra in succeeding years), who had consecrated the Madre de Deus Church in Santhome in 1575 (demolished in 1997). After the British gained possession of the area in the 17th century, the two towns, Madraspattinam and Chennapattinam, eventually merged. The British referred to the united town as Madraspattinam, while the locals preferred to call it Chennapattinam.

The city was officially renamed Chennai in 1996, about the same time that many Indian cities were undergoing name changes. Madras was seen as a Portuguese name.