the word 'unzipped' is a modern english formation built upon the onomatopoeic verb 'zip', which emerged in the late 19th century to imitate a sharp, high-pitched sound. the application of 'zip' to a fastening device, the zipper, occurred in the early 20th century, giving the verb its concrete meaning of fastening or opening with a zipper. the prefix 'un-', of germanic origin and one of the most common in english for expressing reversal, was attached to create the opposite action. the addition of the regular past tense suffix '-ed' completes the word, forming a verb that literally means 'reversed the action of zipping,' which extends logically into the digital realm for decompressing files.

Structure: un (reversal) + zip (fastener) + ped (past tense suffix) un- (old english, prefix denoting reversal or deprivation); zip (onomatopoeic english, imitative of the sound of a fast-moving object, here referring to a fastening device); -ped/-ed (old english, suffix forming the past tense and past participle of regular verbs)