(linguistics) Abbreviation of Proto-Central Algonquian. / (US, law) Abbreviation of Posse Comitatus Act. The U.S. law called "Posse Comitatus Act", 20 Stat. 152 aka 18 U.S.C. § 1385

(aviation) Abbreviation of propulsion controlled aircraft (system/unit), an aircraft with a control system with two or more engines arrayed abreast, allowing descent, ascent, turns by adjusting the throttle control to the engines (sometimes used attributively).

plural of PCA

(US) Acronym of President's Council of Advisors on Science and Technology.

Acronym of passive cavity aerosol spectrometer probe. / Acronym of privately contracted armed security personnel.

plural of PCAT

(Canada, US, countable) Acronym of Pharmacy College Admission Test.

(computing) Acronym of PC as a Service.