In the earlier days when there were not so many means for entertainment, say television, or even radio, in the Indian subcontinent there used to be different shows by people in unorganized way (mostly roadside) and sometimes organized way (fairs, circuses etc.), and they were all called 'Tamasha.' Tamasha comes from the Persian root, where Tamasha means viewing or sight.
Tamasha is an upcoming movie starring Ranbir Kapoor and Deepika Padukone, directed by Imtiaz Ali.
For all the Lyrics Translations from Tamasha, check the link http://www.bollymeaning.com/search/label/Tamasha.