Color symbolism is the use of color as a representation or meaning of something that is usually specific to a particular culture or society. Context, culture and time are certainly important factors to consider when thinking about color symbolism.
Definition of backpack for English Language Learners. : a bag for carrying things that has two shoulder straps and is carried on the back.
Definition of shoulder. 1a : the laterally projecting part of the human body formed of the bones and joints with their covering tissue by which the arm is connected with the trunkb : the region of the body of nonhuman vertebrates that corresponds to the shoulder but is less projecting.