A pall was originally a coffin’s cloak. Now pall usually means that an event or situation is — literally or figuratively — covered in gloom, like disappointing news that casts a pall on your day.
The noun pall comes from the Latin word, pallium, “covering or cloak.” This use of pall has come to mean "gloom" like your grandparents' not being there to celebrate with you that casts a pall over your graduation. The verb pall is used when someone or something becomes boring or less interesting over time. Your initial willingness to perform household chores began to pall when you realized that no one else was willing to chip in.