MAC

(chemistry) Initialism of maximum allowable concentration, the maximum concentration of a pollutant which is considered harmless to healthy adults during their working hours, assuming they breathe uncontaminated air at all other times.

(computer security) Initialism of mandatory access control.

(networking) Initialism of media access control: the portion of Ethernet, Wi-Fi 802.11 wireless, Bluetooth, FDDI, ATM, and Fibre Channel networks that controls which hardware devices have access to the media over which signals are sent.

(aviation) Initialism of mean aerodynamic chord.

(aviation) Initialism of mid-air collision.

(cryptography) Initialism of message authentication code.

(military, nautical, aviation, historical) Initialism of merchant aircraft carrier.

(science fiction) Initialism of magnetic accelerator cannon.

(UK, telecommunications) Initialism of Migration Authorisation Code.

(immunology) Initialism of membrane attack complex, a part of the complement system of the innate immune system.

(computing) Multiply and accumulate: a hardware module found in Digital Signal Processors which performs a multiplication and adds the result of that operation to an accumulator, in a single cycle. Used extensively in implementations of digital filters, transforms and codecs.