com·pact¹ • adj. / kəmˈpakt; käm-; ˈkämˌpakt/ 1. closely and neatly packed together; dense: a compact cluster of houses. ∎  having all the necessary components or features neatly fitted into a small space: a compact car. ∎  (of a person or animal) small, solid, and well-proportioned. ∎  (of speech or writing) concise in expression.2. (compact of) archaic composed or made up of.• v. / kəmˈpakt; käm-/ [tr.] (often be compacted) exert force on (something) to make it more dense; compress: the soil may be compacted by iron oxide. ∎  [intr.] (of a substance) become compressed in this way: the snow hardened and compacted. ∎ archaic form (something) by pressing its component parts firmly together. ∎  express in fewer words; condense: the ideas are compacted into two sentences.• n. / ˈkämˌpakt/ 1. a small flat case containing face powder, a mirror, and a powder puff.2. something that is a small and conveniently shaped example of its kind, in particular: ∎ short for compact car.3. Metallurgy a mass of powdered metal compacted together in preparation for sintering.DERIVATIVES: com·pac·tion / kəmˈpakshən/ n.com·pact·ly adv.com·pact·ness n.com·pac·tor / kəmˈpaktər; käm-; ˈkämˌpaktər/ (also com·pact·er) n.com·pact² • n. / ˈkämˌpakt/ a formal agreement or contract between two or more parties.• v. / kəmˈpakt; käm-; ˈkämˌpakt/ [tr.] make or enter into (a formal agreement) with another party or parties: the Democratic Party compacted an alliance with dissident groups.

compact 2 closely packed or knit together. XIV. — L. compactus, pp. of compingere put closely together, f. COM- + pangere fasten.
Hence compact sb. compact make-up powder, etc. XX. So compact vb. join firmly together. XVI. f. pp. stem of L. compingere.

compact 1 covenant, contract. XVI. — L. compactum, sb. use of n. of pp. of compaciscī make an agreement; see COM-, PACT.

COMPACT

An agreement, treaty, or contract.

The term compact is most often applied to agreements among states or between nations on matters in which they have a common concern.

The Constitution contains the compact clause, which prohibits one state from entering into a compact with another state without the consent of Congress.