The word "它们" is formed by combining two distinct characters: the singular demonstrative pronoun "它" (tā), meaning "it", with the plural suffix "们" (men), which denotes a group. This construction follows a common pattern in Chinese where the suffix "们" is attached to a singular personal or demonstrative pronoun to create a plural form, resulting in a new word that specifically means "they" or "them" when referring to non-human things or animals.