Fc

Fc is an abbreviation used in several unrelated fields. In immunology, Fc refers to the fragment crystallizable region of an antibody, the constant portion that binds to Fc receptors on immune cells and to some components of the complement system. The Fc region determines effector functions such as antibody-dependent cellular cytotoxicity and phagocytosis, and it also interacts with the neonatal Fc receptor (FcRn) to modulate antibody half-life. Therapeutic antibodies and Fc fusion proteins exploit the Fc region to achieve desired pharmacokinetics and immune engagement.

In sports, FC stands for Football Club, a common designation in the names of association football teams, particularly in Europe and Latin America (e.g., FC Barcelona). It is used regardless of whether the club plays in a football-only league or a multi-sport organization.

In physics, F_c denotes centrifugal force, a fictitious force encountered in rotating reference frames; it is proportional to mass, angular velocity squared, and radius (F_c = m r ω^2) and is used to analyze circular motion alongside centripetal force.

In chemistry and materials science, Fc denotes a ferrocene moiety (ferrocenyl) and is used as a shorthand in organometallic contexts; compounds are sometimes described as Fc-substituted or Fc-terminated.

This concise overview covers primary uses; context usually clarifies which Fc is meant.