160+ Science Words That Start With I: Complete List With Meanings

Science is full of fascinating words that start with I. Learning them can boost your knowledge and make understanding science much easier for students and enthusiasts alike.

This article explains 160+ science words starting with I across different fields like computer, physical, life, space, and environmental sciences. You’ll also find words suitable for kids and students from 5th to 8th grade, each with simple meanings for easy understanding.

Computer Science Words That Start With I

Word	Meaning
Interface	A point of interaction between computer components or user and system
Integer	A whole number without fractional or decimal components
Input	Data or instructions entered into a computer system
Algorithm	A step-by-step procedure for solving a problem (though starts with A, “Iterative algorithm” uses I)
Iteration	Repetition of a process or set of instructions in programming
Interpreter	A program that executes code line by line without prior compilation
Implementation	The process of putting a design or plan into executable code
Instruction	A command given to a computer to perform a specific operation
Identifier	A name used to identify a variable, function, or other entity in code
Infrastructure	The underlying foundation or framework of a computing system
Integration	Combining different software components or systems to work together
Initialization	The process of assigning an initial value to a variable
Interrupt	A signal that temporarily stops the current process to handle an urgent task
Instance	A specific occurrence or realization of a class in object-oriented programming
Index	A reference point or position indicator in data structures

Physical Science Words That Start With I

Word	Meaning
Inertia	The tendency of an object to resist changes in its state of motion
Ion	An atom or molecule with a net electric charge
Isotope	Atoms of the same element with different numbers of neutrons
Ionization	The process of adding or removing electrons to create ions
Incandescence	Light emission from a heated substance
Insulator	A material that resists the flow of electricity or heat
Interference	The interaction of two or more waves resulting in a new wave pattern
Impulse	The change in momentum of an object when force is applied
Incline	A sloped surface used to study forces and motion
Inductance	The property of a conductor that opposes changes in electric current
Isobar	Lines on a map connecting points of equal atmospheric pressure
Immiscible	Liquids that do not mix together to form a homogeneous solution
Ignition	The process of starting combustion or burning
Incandescent	Emitting light as a result of being heated
Isotherm	A line connecting points of equal temperature

Life Science Words That Start With I

Word	Meaning
Immune	Protected against a particular disease or pathogen
Invertebrate	An animal without a backbone or spinal column
Inheritance	The passing of genetic traits from parents to offspring
Ingestion	The process of taking food or drink into the body
Insulin	A hormone that regulates blood sugar levels
Instinct	An innate behavioral response not based on learning
Incubation	The process of keeping eggs warm until they hatch
Infection	The invasion and multiplication of microorganisms in body tissues
Inflammation	The body’s protective response to injury or infection
Invasive	A non-native species that spreads and causes harm to an ecosystem
Inoculation	Introduction of a vaccine or pathogen to produce immunity
Iris	The colored part of the eye that controls pupil size
Intestine	The tubular organ where digestion and nutrient absorption occur
Incubator	A controlled environment for developing organisms or cultures
Immunity	The body’s ability to resist infection and disease

Space Science Words That Start With I

Word	Meaning
Interstellar	Located or occurring between stars
Ionosphere	A layer of Earth’s atmosphere containing ionized particles
Impact crater	A depression formed by a celestial object striking a surface
Irregular galaxy	A galaxy without a distinct regular shape
Infrared	Electromagnetic radiation with wavelengths longer than visible light
Inclination	The angle between an orbital plane and a reference plane
Intergalactic	Existing or occurring between galaxies
Inner planets	The four rocky planets closest to the Sun
Ice giant	A large planet composed mainly of water, methane, and ammonia
Interplanetary	Located or occurring between planets
Io	One of Jupiter’s largest moons, known for volcanic activity
Irradiance	The power of electromagnetic radiation per unit area
Infrared astronomy	The study of celestial objects using infrared radiation
International Space Station	A habitable artificial satellite orbiting Earth
Impact event	A collision between astronomical objects

Environmental Science Words That Start With I

Word	Meaning
Invasive species	Non-native organisms that harm ecosystems
Irrigation	The artificial application of water to land for agriculture
Indicator species	Organisms that reflect the environmental conditions of their habitat
Incineration	The process of burning waste materials at high temperatures
Indigenous	Native or naturally occurring in a particular region
Industrial pollution	Contamination caused by manufacturing and industrial processes
Infiltration	The process of water soaking into soil
Insecticide	A chemical substance used to kill insects
Interdependence	The mutual reliance between organisms in an ecosystem
Introduced species	An organism brought to a new area by human activity
Impermeable	Not allowing water or other fluids to pass through
Inorganic	Matter that does not contain carbon-hydrogen bonds
Incinerator	A facility designed to burn waste materials
Island ecosystem	A self-contained ecological community on an island
Integrated pest management	A sustainable approach to managing pests

Science Words That Start With I With Meaning

Word	Meaning
Isotonic	Having equal osmotic pressure or solute concentration
Igneous rock	Rock formed from cooled and solidified magma or lava
Illumination	The action of supplying or brightening with light
Induction	The process of deriving general principles from specific observations
Indicator	A substance that changes color to show chemical conditions
Imago	The final adult stage of insect development
Imbibition	The absorption of water by a solid substance
Immune system	The body’s defense mechanism against disease
Impervious	Not allowing passage through, especially of fluids
Incremental	Occurring in small successive stages or degrees
Incandescent bulb	A light source that produces light through heating
Immersion	The action of placing something completely in a liquid
Isothermal	Occurring at constant temperature
Irradiation	Exposure to radiation or the process of emitting radiation
Ionic bond	A chemical bond formed by electron transfer between atoms

Science Words That Start With I For Kids

Word	Meaning
Ice	Frozen water in solid form
Insect	A small animal with six legs and three body parts
Iron	A common metal that is magnetic and can rust
Investigate	To examine or study something carefully
Inventor	A person who creates something new
Inside	The inner part or interior of something
Ivy	A climbing plant with evergreen leaves
Iguana	A large tropical lizard with a spiny back
Ice cube	A small block of frozen water
Icicle	A hanging piece of ice formed from dripping water
Ingredient	One of the parts that make up a mixture
Island	Land surrounded by water on all sides
Invention	Something new that has been created
Identify	To recognize or name something
Increase	To become or make something larger or greater

Science Words That Start With I 5th Grade

Word	Meaning
Igneous	Relating to rock formed from volcanic activity
Invertebrate	An animal without a backbone
Insulator	A material that prevents heat or electricity from passing through
Inheritance	Traits passed from parents to offspring
Intestine	The organ where food is digested and absorbed
Ice cap	A thick layer of ice covering a polar region
Imprint	A mark or impression left by pressure
Inclined plane	A flat surface tilted at an angle, used as a simple machine
Instinct	A natural behavior animals are born with
Iron filings	Small pieces of iron used to show magnetic fields
Incomplete metamorphosis	A type of insect development with three life stages
Intermolecular	Forces occurring between molecules
Iodine	A chemical element essential for thyroid function
Iris diaphragm	The adjustable opening in a microscope that controls light
Isopod	A type of crustacean with seven pairs of legs

Science Words That Start With I 6th Grade

Word	Meaning
Inertia	The resistance of an object to changes in motion
Ion	An atom with an electric charge
Ionization	The process of forming ions
Isotope	Atoms of the same element with different neutron numbers
Igneous rock	Rock formed from cooled molten material
Immune response	The body’s reaction to foreign substances
Indicator solution	A chemical that changes color under different conditions
Infiltration	Water seeping into the ground
Infrared radiation	Heat energy invisible to the human eye
Insectivore	An organism that eats insects
Interdependence	How organisms rely on each other in ecosystems
Intrusive rock	Igneous rock that forms below Earth’s surface
Involuntary muscle	Muscles that work without conscious control
Ionic compound	A substance formed from ions bonded together
Isobar	A line connecting areas of equal air pressure

Science Words That Start With I 7th Grade

Word	Meaning
Interference	The interaction of waves that meet
Impulse	Force applied over a time interval, changing momentum
Induction	The process of inducing electric current or magnetism
Isotonic solution	A solution with equal solute concentration as another
Immune system	The network of cells and organs defending against disease
Independent variable	The factor changed in an experiment
Intensity	The amount of energy transmitted per unit area
Intermolecular force	Attractive forces between molecules
Intrusive igneous	Rock that crystallizes beneath Earth’s surface
Ionosphere	The atmospheric layer containing charged particles
Imbibition	The absorption of liquid by a solid colloid
Incandescence	Light produced by heating a substance
Invasive species	Non-native organisms disrupting ecosystems
Ionic radius	The measure of an ion’s size
Isoelectronic	Atoms or ions with the same electron configuration

Science Words That Start With I 8th Grade

Word	Meaning
Inertial frame	A reference frame moving at constant velocity
Ionic bond	Chemical bond formed by electron transfer
Isomer	Molecules with identical formulas but different structures
Isothermal process	A thermodynamic process at constant temperature
Impulse-momentum theorem	The relationship between impulse and momentum change
Indicator species	Organisms signaling environmental health
Induced current	Electric current created by changing magnetic fields
Insoluble	Unable to dissolve in a particular solvent
Ionizing radiation	Radiation with enough energy to remove electrons
Interphase	The stage between cell divisions when growth occurs
Igneous intrusion	Magma that solidifies within existing rock layers
Incomplete dominance	A genetic pattern where neither allele is fully dominant
Innate immunity	The non-specific defense system present at birth
Isobaric process	A thermodynamic process at constant pressure
Isochoric process	A thermodynamic process at constant volume

Final Thoughts

Exploring 150+ science words that start with I can make learning fun and boost your knowledge in every field. From computer to environmental science, these words help you understand concepts easily and remember them for daily use and studies.

Start using these words today to impress teachers, friends, or colleagues with your science vocabulary. Keep practicing, explore their meanings, and watch your understanding of science grow. Don’t wait, dive deeper into each category and make learning exciting and rewarding.