1.
If you ~ something such as a piece of clothing or if it zips up, you are able to fasten it using its zip.
He zipped up his jeans...
My jeans wouldn’t ~.
PHRASAL VERB: V P n (not pron), V P, also V n P
2.
To ~ a computer file means to compress it so that it needs less space for storage on disk and can be transmitted more quickly. (COMPUTING)
These files have been zipped up to take up less disk space so they take less time to download.
PHRASAL VERB: V P, also V P n