- C2IEDM or C2IEDM(Command and Control Information Exchange Data Model)
- C2IP(Command and Control Initiatives Program)
- C2IPS(Command and Control Information Processing System)
- C2IS(Command and Control Information System)
- C2IS or C2IS(Command and Control Information System)
- C2MAA(Command and Control Mission Area Analysis)
- C2MADP(Command and Control Mission Area Development Plan)
- C2MAMP(Command and Control Mission Area Materiel Plan)
- C2MUG(Command and Control Microcomputer Users Group)
- C2 or C2(Command and Control)
- C2P(Command and Control Planning)
- C2PC or C2PC(Command and Control Personal Computer)
- C2-Protect(Command and Control warfare - Defensive)
- C2S(Command and Control Support)
- C2S2(Command, Control, and Subordinate Systems)
- C2SA-E(Command and Control Support Activity-Europe)
- C2SPR(Command and Control System Program Review)
- C2T2(Close Combat Tactical Trainer)
- C2V(Command and Control Vehicle)
- C2V or C2V(Command and Control Vehicle)
- C2W(Command and Control Warfare)
- C2W or C2W(Command and Control Warfare)
- C-2X(Coalition Intelligence Directorate, Counter-intelligence and Human Intelligence Staff Element)
- C3(propane)
- C3AG(Command, Control, and Communications Advisory Group)
- C3CM(Command, Control, and Communications Countermeasures)
- C3I(Command, control, communications, and intelligence)
- C3IC(Coalition Coordination, Communications, and Integration Center)
- C3IEW(Command, Control, Communications, Intelligence, and Electronic Warfare)
- C3I or C3I(Command, Control, Communications, and Intelligence)
- C3MP(Command, Control, and Communications Master Plan)
- C3 or C3(Colorectal Cancer Condition||Command, Control, and Communications)
- C3S(Command, Control, and Communications Systems)
- C3SMP(Command, Control, and Communications Systems Master Plan)
- C4(butane)
- C-4(Composition C-4 plastic explosive)
- C4AH(Center for Advanced Hindsight)
- C4CM(Command, Control, Communications, and Computer Counter-Measures)
- C4D(Cinema 4D)
- C4I(Command, Control, Communications, Computers, and Intelligence)
- C4IFTW(Command, Control, Communications, Computers, and Intelligence For The Warrior)