dhuni = tune
Bhagat Gurdas ji ne jado Adi Granth likheya Guru Arjan Dev ji de aadesh utte, eh ohdon likhey gaye si harek shabad de layi jis nu gayen karan layi ik tune (dhuni) varti jandi hai.

The list of vars, with corresponding dhunis, are:
1. Var Majh by Nanak I Malak Murid tatha Chandrahara Sohia ki dhuni (GG, 137).
2. Gauri ki Var by Nanak V Rai Kamaldi Mojdi ki Var ki dhuni (GG, 318).
3. Asa ki Var by Nanak I Tunde Asrajai ki dhuni (GG, 462).
4. Gujari ki Var by Nanak III Sikandar Birahim ki Var ki dhuni (GG, 508).
5. Vadahans ki Var by Nanak IV Lalan Bahalima ki dhuni (GG, 585).
6. Ramkali ki Var by Nanak III Jodhai Virai Purabani ki dhuni (GG, 947).
7. Sarang ki Var by Nanak IV Rai Mahme Hasane ki dhuni (GG, 1237).
8. Var Malar Ki by Nanak I Rane Kailas tatha Mal de ki dhuni (GG, 1278).
9. Kanare ki Var by Nanak IV Muse ki Var ki dhuni (GG, 1312).


Reference: The Sikh Encyclopedia