- Inorganic ions
- Inorganic polymers
- Inorganic waste
- Inosine
- Inosine monophosphate
- Inositol
- Inositol phosphate
- Inositol phosphate metabolism
- Inositol trisphosphate
- Inotropes
- Inotropic
- Inpainting
- Input devices
- Input impedance
- Input offset voltage
- Input-to-state stability
- Inquiry
- Inrush current
- Inscribed
- Inscribed angle
- Inscribed sphere
- Insect flight
- Insect repellents
- Insensitive munitions
- Insertion devices
- Insertion gain
- Insertion loss
- Insertion reactions
- Insertion sequence
- Insertion sort
- Insider threat
- Inspection
- Inspection in manufacturing
- Instability
- Instability index
- Installation
- Installer
- Instance selection
- Instance variable
- Instance-based learning
- Instant centre of rotation
- Instant coffee
- Instant messaging
- Instant-on
- Instantaneous frequency
- Instantons
- Instruction list
- Instruction pipeline
- Instruction register
- Instruction set
- Instructional design
- Instrument amplifier
- Instrument approach
- Instrument error
- Instrument transformer
- Instrumental analysis
- Instrumentation
- Instrumentation amplifier
- Instruments
- Insufflation
- Insula
- Insular cortex
- Insulated glazing
- Insulating Concrete Form
- Insulation
- Insulation system
- Insulators
- Insulin
- Insulin glargine
- Insulin pumps
- Insulin receptor
- Insulin receptor substrate
- Insulin-like growth factor
- Insulin-like growth factor 1
- Insulin-like growth factor 1 receptor
- Insulin-like growth factor 2
- Insulinoma
- Insult
- IntServ
- Intact forests
- Intake
- Intake manifold
- Intake tower
- Intangible assets
- Integer factorization
- Integer lattice
- Integer overflow
- Integer programming
- Integer sequences
- Integer-valued function
- Integers
- Integrable systems
- Integral
- Integral curves
- Integral domains
- Integral equations
- Integral geometry
- Integral imaging
- Integral length scale
- Integral membrane proteins
- Integral nonlinearity
- Integral operator
- Integral transforms
- Integral windup
- Integrase inhibitors
- Integrated Risk Information System
- Integrated assessment model
- Integrated design
- Integrated encryption scheme
- Integrated logistics support
- Integrated passive devices
- Integrated project delivery
- Integrating factors
- Integrating sphere
- Integration by parts
- Integration by substitution
- Integrative thinking
- Integrator
- Integrins
- Integrity
- Integro-differential equation
- Integrons
- Integument
- Integumentary system
- Inteins
- Intel 4004
- Intel Core
- Intel Core 2
- Intel Edison
- Intel IPSC
- Intel Paragon
- Intellectual disability
- IntelliJ IDEA
- Intelligence
- Intelligence amplification
- Intelligent agents
- Intelligent automation
- Intelligent control
- Intelligent decision support system
- Intelligent decision support systems
- Intelligent lighting
- Intelligent maintenance system
- Intelligent pump
- Intelligent sensor
- Intelligent tutoring system
- Intelligibility
- Intensity
- Intensity interferometer
- Intensity measure
- Intensity modulation