An internship is an official program offered by an employer to potential employees to mould their skills. Interns work and learn either part time or full time at a company for a certain period of time. Internships are most popular with undergraduates or graduate students who work between one to four months and have a goal to gain knowledge in practical work or research related experience.
The modern concept of internships essentially evolved from the concept of apprenticeship, in which skilled laborers (often craftsmen) would teach a young person their trade and, in exchange, that person would agree to work for the teacher for a certain length of time.
It is now in this generation, where technologies evolve on a faster mode that one needs to be updated about the latest upgradations.