https://www.merriam-webster.com/dictionary/tambura
The meaning of TAMBOURA is an Asian musical instrument resembling a lute in construction but without frets and used to produce a drone accompaniment to singing.
merriam webstertamburadefinitionmeaning
https://www.hacklemanshop.com/dhrupad-tambura.html
HERE IS A SOUND SAMPLE
dhrupadtambura