Alap
The alap (/æˈlɑːp/; Hindustani: [aːˈlaːp]) is the opening section of a typical North Indian classical performance. It is a form of melodic improvisation that introduces and develops a raga. In dhrupad singing the alap is unmetered, improvised (within the raga) and unaccompanied (except for the tanpura drone), and started at a slow tempo.