China 
Africa 
- Imprecise probability
- Improper integrals
- Improper rotation
- Impulse
- Impulse C
- Impulse generator
- Impulse noise
- Impulse response
- Impulsivity
- Impurities
- Impurity
- Imputation
- In silico
- In situ bioremediation
- In situ chemical oxidation
- In situ chemical reduction
- In situ conservation
- In situ leach
- In situ polymerization
- In-circuit testing
- In-gel digestion
- In-group favoritism
- In-memory
- In-memory database
- In-memory processing
- In-phase and quadrature components
- In-place algorithm
- In-situ leaching
- In-vessel composting
- InChI
- InGaAs
- InGaAsP
- InGaN
- InGaP
- InSAR
- Inborn errors of metabolism
- Inbred
- Inbreeding depression
- Incandescent
- Incandescent light bulb
- Incenter
- Inceptionv3
- Inch of mercury
- Inch of water
- Inches
- Inches of water
- Incidence
- Incidence matrix
- Incidence structure
- Incident management
- Incineration
- Incinerator bottom ash
- Incipient wetness impregnation
- Incisions
- Inclination
- Inclined orbit
- Inclined plane
- Inclinometers
- Inclusion bodies
- Inclusion compounds
- Inclusions
- Inclusive design
- Incoherent scatter
- Incoloy
- Income approach
- Incompatible elements
- Incompressible
- Incompressible flow
- Inconel
- Inconel 625
- Incongruent melting
- Inconsistent
- Incorporated engineer
- Incoterms
- Incremental Dynamic Analysis
- Incremental deformations
- Incremental encoder
- Incremental learning
- Incremental sheet forming
- Incretins
- Incubation period
- Incubator
- Incus
- Indazole
- Indels
- Indene
- Indentation
- Indentation hardness
- Indentation size effect
- Independence of irrelevant alternatives
- Independent
- Independent and identically distributed
- Independent and identically distributed random variables
- Independent equation
- Independent increments
- Independent sets
- Independent sideband
- Independent suspension
- Independent variable
- Indeterminate
- Indeterminate forms
- Index
- Index ellipsoid
- Index finger
- Index notation
- Index set
- Indexable
- Indexing
- Indexing heads
- India's three-stage nuclear power programme
- Indian National Committee for Space Research
- Indian National Satellite System
- Indian Plate
- Indian buffet process
- Indian childhood cirrhosis
- Indicated airspeed
- Indications
- Indicator bacteria
- Indicator diagram
- Indicator function
- Indicator organism
- Indicator species
- Indicator vectors
- Indicators
- Indifference curve
- Indigestion
- Indigo
- Indigo carmine
- Indigo dye
- Indirect DNA damage
- Indirect branch
- Indirect calorimetry
- Indirect costs
- Indirect injection
- Indirect pathway
- Indirect utility function
- Indirection
- Indiscernibles
- Indium
- Indium antimonide
- Indium arsenide
- Indium gallium arsenide
- Indium gallium nitride
- Indium gallium phosphide
- Indium iodide
- Indium nitride
- Indium oxide
- Indium phosphide
- Indium selenide
- Indium sulfate