CR4 may refer to:

Science and technology

Complement receptor 4 Macrophage-1 antigen (or integrin αMβ2 or macrophage integrin or Mac-1) is a complement receptor ("CR3") consisting of CD11b (integrin αM) and CD18 (integrin β2). The integrin α chain is noncovalently bound to the integrin β chain. It binds ...

, a

complement receptor A complement receptor is a membrane-bound receptor belonging to the complement system, which is part of the innate immune system. Complement receptors bind effector protein fragments that are produced in response to antigen-antibody complexes or ...

in the immune system * CR4, a

control register A control register is a processor register that changes or controls the general behavior of a CPU or other digital device. Common tasks performed by control registers include interrupt control, switching the addressing mode, paging control, and ...

in the x86 CPU architecture * 100GBASE-CR4 and 40GBASE-CR4, in

100 Gigabit Ethernet 40 Gigabit Ethernet (40GbE) and 100 Gigabit Ethernet (100GbE) are groups of computer networking technologies for transmitting Ethernet frames at rates of 40 and 100 gigabits per second (Gbit/s), respectively. These technologies offer significantly ...

and 40 Gigabit Ethernet

Other uses

* CR4, four-firm

concentration ratio In economics, concentration ratios are used to quantify market concentration and are based on companies' market shares in a given industry. A concentration ratio (CR) is the sum of the percentage market shares of (a pre-specified number of) t ...

, a measure of market concentration in economics * CR4, a postcode district in the

CR postcode area The CR postcode area, also known as the Croydon postcode area, is a group of eight postcode districts in England, within ten post towns. These cover parts of southern Greater London and north-east Surrey. The main sorting office is in Croydon ...

in England *

Pasir Ris East MRT station Pasir Ris East MRT station is a future underground Mass Rapid Transit (Singapore), Mass Rapid Transit station on the Cross Island MRT line located in Pasir Ris, Singapore. It will be located along Pasir Ris Drive 1, between Pasir Ris Street 12 ...

(CR4), an upcoming MRT station on the Cross Island Line in Singapore {{Letter-NumberCombDisambig