Kedah, the west coast of Malaya, is known as Kadaram in Tamil. Kadaram kandan, “conqueror of Kadaram” was one of the attributes given to Rajendra Cholan I of the Tamil Chola empire of the early 11th century A.D. There is also a place in the Madurai District in Tamil Nadu, of the Pandyan Empire, with the name Kadaram.
A large and round fruit, which is a species of orange, with sour and bitter taste (not grapefruit) is called by the Tamils as kadarangkay, kadaram-pulp. This variety of orange was brought by the Tamil traders from Malaysia to Tamil Nadu, or the place abounded by this pulp could have been named after it by the Tamil settlers in Malaya.
Kedah in the Malay language means 'open wide' which is apt as Kedah is primarily made of padi fields which as flatlands. So Negeri Kedah would be 'Wide Open State'. Place names in Malaysia tend to be Malay words that describe the nature of the place or the plants or animals that are abundant there.
