(Singapore, slang) Initialism of pa chew cheng.

(electronics) Abbreviation of peripheral clock.

(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).

Abbreviation of pentachloronitrobenzene.

(regular expressions) Initialism of Perl-compatible regular expressions.

Initialism of Patent Cooperation Treaty.

(military) Abbreviation of platoon combat team.

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

(computing) PCI (the computer bus), as opposed to the newer PCI Express.