ཀླད་ཀོར།

klad kor:

The Tibetan word klad kor means (a) a small circle (i.e. °), standing for anusvāra, and nowadays (b) zero is called klad kor (modern) or thig kor (classical). But what about is etymology? Actually it is a “circle (kor) above (klad).” This etymology has been recognised also in the Tshig mdzod chen mo (s.v. klad skor 2): yi ge’i klad kyi thig kor te legs sbyar gyi yi ge’i klad du bris pa’i dbyibs sgor sgor gyi rtags la zer |.