compact: There are two distinct words compact in English; both are of Latin origin, but they come from completely different sources. The adjective, ‘compressed’ [14], comes from Latin compactus, the past participle of compingere, a compound verb formed from com- ‘together’ and pangere ‘fasten’. The noun use ‘small case for face powder’ is 20th-century and based on the notion of firmly compacted powder. Compact ‘agreement’ [16] comes from Latin compactum, a noun based on the past participle of the verb compacīscī ‘come to an agreement’. The unprefixed form pacīscī, a relative of Latin pax ‘peace’, gave English pact [15]. => pact, peace
compact (adj.)
late 14c., from Middle French compact (14c.) or directly from Latin compactus "concentrated," past participle of compingere "to fasten together, construct," from com- "with, together" (see com-) + pangere "to fix, fasten" (see pact). Compact car is 1960. Compact disc is from 1979.
compact (n.1)
"agreement," 1590s, from Latin compactum "agreement," noun use of neuter past participle of compacisci "come to agreement," from com- "together" (see com-) + pacisci "to covenant, contract" (see pact).
compact (v.)
early 15c., from Latin compactus, past participle of compingere "to fasten together" (see compact (adj.)). Related: Compacted; compacting.
compact (n.2)
"make-up case," 1921, from compact (adj.), based on its containing compacted face powder.