pack (n.) Look up pack at Dictionary.com
"bundle," early 13c., probably from a Low German word (compare Middle Dutch pac, pack "bundle," Middle Low German pak, Middle Flemish pac, attested from late 12c.), originally a term of wool traders in Flanders; or possibly from Old Norse pakki. All are of unknown origin.

Italian pacco is a Dutch loan word; French pacque probably is from Flemish. Meaning "set of persons" (usually of a low character) is c.1300, older than sense of "group of hunting animals" (early 15c.). Extended to collective sets of playing cards (1590s), floating ice (1791), cigarettes (1924), and submarines (1943). Meaning "knapsack on a frame" is attested from 1916. Pack of lies first attested 1763.
pack (v.) Look up pack at Dictionary.com
c.1300, "to put together in a pack," from pack (n.), possibly influenced by Anglo-French empaker (late 13c.) and Medieval Latin paccare "pack."

Some senses suggesting "make secret arrangement" are from an Elizabethan mispronunciation of pact. Sense of "to carry or convey in a pack" (1805) led to general sense of "to carry in any manner;" hence to pack heat "carry a gun," underworld slang from 1940s; "to be capable of delivering" (a punch, etc.), from 1921. Related: Packed; packing.