In ancient Greece, the word ethnos was used to refer to a distinct ‘people’.
In the 1940s, researchers seeking to find a replacement for the word ‘race’—a word that had become associated with the genocidal policies of the Nazis—chose the word ‘ethnicity.
‘Ethnic’ in contemporary usage then refers to a type of social stratification that emerges when people form groups based on their real or perceived origins. Members of ethnic groups believe that their specific ancestry and culture mark them as different from others.
Though there is a tendency to refer to minority groups as ‘ethnic’, this is not correct usage as, in fact, everyone has an ethnic background, whether acknowledged or not. Nor can ‘ethnicity be interchangeably used with ‘race’; the most basic difference between the two words is that ethnic affiliation comes from inside a group and ethnicity is a process of self- definition while race is really an external force that is imposed upon groups to differentiate them.
Ethnicity as an affiliation may naturally emerge as people are socialised into cultures with long histories; the children born into ethnic groups develop deep seated attachment to them. So, cultural elements—language, faith, customs, beliefs and traditions of specific groups are passed on within groups. There is also the other view that ethnic attachments arise in specific contexts, for specific reasons. We see evidence of both in India.
Although diversity is quite pronounced, it cannot be over-emphasised. A long drawn process of continuous contact, intermixing and later modifications have created a broad ethnic uniformity. The apparent racial similarities and differences are only indicators of some past association with a certain racial stock.
Despite the tremendous diversity one can say that there exists a physical type which is typically Indian. All South Asians whether they belong to Pakistan, India, Bangladesh or Sri Lanka carry this stamp of distinction.