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.
Learner's definition of SACK. 1. [count] : a bag that is made of strong paper, cloth, or plastic. a sack containing flour = a sack of flour. sacks of cement. a grocery sack.