It's the Tibetan syllable TAM, the seed syllable of the female buddha Tara (sanskrit) or Dölma (tibetan), which translates as Liberatress. As it is white here, it stands for the White Tara, which especially gives the blessings for a long life:
Thangka painting is a uniquely Tibetan tradition that evolved between the and centuries. Its origins lay in Indian religious art, but Nepalese, Chinese and Kashmiri styles also influenced its development.
Green Tara (Tib. སྒྲོལ་མ, Drolma) or Ārya Tārā, also known as Jetsun in Tibetan Buddhism, is a female Bodhisattva in Mahayana Buddhism who appears as a female Buddha in Vajrayana Buddhism. She is known as the “mother of liberation”, and represents the virtues of success in work and achievements. #ColoringForMeditation #TibetanArt #TibetanColoring #Thangka #BuddhistArt #BuddhistColoring