Light classical usually refers to vocal performances and is sometimes called, simply, geet (song). In general these songs tend to be shorter pieces that do not adhere to the stark, complex rules associated with classical forms like dhrupad. Light classical music has gained in popularity over the past several decades, thanks in part to singers Jagjit and Chitra Singh, who, some argue, revived the dying art form. The genre also gained popularity in film; all the great film singers perform light classical forms like ghazal, a Persian poetic style set to music that migrated to India centuries ago. (The word originally means "discourse" or "talk to a woman" and consists primarily of romantic couplets.) Another recently popular form is thumri, which is simultaneously romantic and devotional, and revolves around a young girl's love of Krishna. Dadra is less common, but it's very similar to thumri, except it allows the singer more room for improvisation. Tappa is a lesser-known Punjabi form of light classical. Famous proponents of light classical singing include Asha Bhosle, Begum Akhtar, Mukesh, Habib Wali Mohammed, Shobha Gurtu and Farida Khanum.