Editing If (section)

==Science and technology==
===Biology and medicine===
* [[Funny current|''I''<sub>''f''</sub> current]], a component current in the cardiac pacemaker potential
* [[Immunofluorescence]], a form of labeling substances with fluorescent antibodies
* [[Initiation factor]], an important component in protein synthesis
* [[Intermediate filament]], a component of the cytoskeleton
* [[Interstitial fluid]], the liquid outside of a cell
* [[Intrinsic factor]], produced by the stomach

===Computing and mathematics===
* [[If-then-else]], a conditional statement in computer programming
* [[IF (x86 flag)]], the Interrupt Flag in the x86 processor architecture
* [[Kalman filter#Information filter|Information filter]], or inverse covariance filter, in Kalman filtering
* [[Interface (computing)]], a shared boundary across which components of a computer system exchange information
* [[Intermediate form]], a type of data structure in computer programming

===Other uses in science and technology===
* [[Information filtering system]], which removes redundant or unwanted information at a semantic level
* [[Intelligent falling]], a satirical "alternative theory" of gravitation
* [[Intermediate frequency]], in radio transmission or reception
* [[Internal focusing]], a lens technology in which focusing occurs only with internal elements
* [[Iodine monofluoride]], an unstable interhalogen inorganic compound
* [[International Fujita scale]] (IF-scale), a scale to rate a tornado's intensity