If you describe something as filial, you're saying it's offspring-related. Depending on who your parents are, your filial duties might include taking out the trash, or washing dishes, or ruling empires.
The word filial comes from the Latin words filius, which means "son," and filia, or daughter. In other words, filial is the filius of filius. One way of remembering the word is to the think of a filly, a young horse. The two words aren't related, but it's fun to put them in the same sentence: "The filly's filial love made the mare a happy mom."