The crossword solution for the term 'burden-bearing beast' is ASS, which is a three-letter word. An ASS, also known as a donkey, is a domesticated member of the Equidae family, which includes horses and zebras. Asses are used as beasts of burden, meaning they are used to carry heavy loads or pull carts. They have been used for this purpose since ancient times, and are still used in many parts of the world today.