From the verb ܛܵܒ݂ܸܥ (ṭāḇiˁ, “to fall asleep”).
ܛܒ݂ܝܼܥܵܐ • (ṭḇīˁā) (feminine ܛܒ݂ܝܼܥܬܵܐ (ṭḇīˁtā), plural ܛܒ݂ܝܼܥܹ̈ܐ (ṭḇīˁē))