100+ Science Words that Start With O

Explore science words that start with o.

Science Words that Start With O

Here are 100 science words that start with “O”:

  • Oxygen
  • Organism
  • Oscillation
  • Orbit
  • Osmosis
  • Optics
  • Ozone
  • Organ
  • Observation
  • Organic
  • Ovary
  • Offspring
  • Objective
  • Operator
  • Oxidation
  • Olfactory
  • Overpopulation
  • Osmoregulation
  • Olfaction
  • Ontogeny
  • Oocyte
  • Outlier
  • Origin
  • Optimum
  • Oligonucleotide
  • Opsonization
  • Osseous
  • Oncogene
  • Operator gene
  • Omnidirectional
  • Orthogonal
  • Operon
  • Oviparous
  • Overlapping
  • Optogenetics
  • Ontology
  • Orthopedics
  • Oogenesis
  • Overdose
  • Oxidative stress
  • Osmolarity
  • Orbital
  • Organogenesis
  • Oncology
  • Osteoblast
  • Overexpression
  • Osmotic pressure
  • Ontological
  • Ornithology
  • Optic nerve
  • Olfactory bulb
  • Outer space
  • Optimal growth
  • Organ system
  • Outcrossing
  • Overweight
  • Olfactory receptor
  • Oncofetal antigen
  • Ossification
  • Orthologous
  • Organ transplant
  • Objectivity
  • Ovarian follicle
  • Outcrop
  • Oviparity
  • Optical illusion
  • Osmoreceptor
  • Ovary cancer
  • Osteoclast
  • Osmotic potential
  • Oviposition
  • Onychomycosis
  • Orthodontics
  • Octahedral
  • Outgassing
  • Organellar
  • Overhunting
  • Oxidative phosphorylation
  • Oligosaccharide
  • Open system
  • Outer membrane
  • Ornamental
  • Optic chiasm
  • Oncolytic virus
  • Osteocyte
  • Oxygenation
  • Ovipositor
  • Ocular
  • Oncogenic
  • Osteoporosis
  • Obligate
  • Odontoblast
  • Oxytocin
  • Organophosphate
  • Ozone layer
  • Olfactory cortex
  • Osmolality
  • Oculomotor
  • Overdominance

Related: Science Words A to Z

science words that start with o

Science Words That Start With O (By Grade)

Science Words That Start With O (4th Grade):

  • Oxygen
  • Orbit
  • Organism
  • Ocean
  • Observation
  • Ozone
  • Owl
  • Octopus
  • Optics
  • Offspring
  • Object
  • Oil
  • Onion
  • Oar
  • Orbit
  • Opal
  • Oak
  • Oxygenate
  • Oscillate
  • Oarfish

Science Words That Start With O (5th Grade):

  • Oxygen
  • Orbit
  • Organism
  • Oceanography
  • Observation
  • Ozone layer
  • Omnivore
  • Optics
  • Offspring
  • Objectivity
  • Oil spill
  • Onion cell
  • Oscillation
  • Organic compound
  • Oxidation
  • Odorant
  • Osmosis
  • Osmoregulation
  • Outcrop
  • Orogeny

Science Words That Start With O (6th Grade):

  • Organic chemistry
  • Osmotic pressure
  • Oxygenation
  • Organic molecule
  • Oscilloscope
  • Ozone depletion
  • Ocular anatomy
  • Oogenesis
  • Outlier
  • Oligonucleotide
  • Osmotic potential
  • Organ system
  • Oxidative stress
  • Osmotic equilibrium
  • Open circuit
  • Optimal growth
  • Oceanic crust
  • Olfactory receptor
  • Oxidative phosphorylation
  • Osteoblast

Science Words That Start With O (7th Grade):

  • Oogenesis
  • Organic synthesis
  • Osteoporosis
  • Oxidative damage
  • Optogenetics
  • Osmoreceptor
  • Osmotic regulation
  • Oligosaccharide
  • Omics technologies
  • Ocean acidification
  • Operant conditioning
  • Orthopedics
  • Oxidative metabolism
  • Oncogene
  • Oviparous
  • Orthogonal projection
  • Oxidative stress response
  • Osmoregulatory hormone
  • Optical coherence tomography
  • Olfactory bulb

Science Words That Start With O (8th Grade):

  • Organic synthesis
  • Oncolytic virus
  • Osmoregulation mechanism
  • Oxidative damage repair
  • Opioid receptor
  • Optical fiber
  • Oogenesis process
  • Oligodendrocyte
  • Oxytocin hormone
  • Oxidative folding
  • Olfactory cortex
  • Optical tweezer
  • Ozone depletion potential
  • Open-field test
  • Oxyfuel combustion
  • Ovulation induction
  • Optical coherence microscopy
  • Olfactory discrimination
  • Oncolytic virotherapy
  • Orthopedic surgery

Science Words Starting With O (By Subject)

Physics Words That Start With O:

  • Oscillation
  • Ohm
  • Optics
  • Orbit
  • Oscilloscope
  • Ohm’s law
  • Observational study
  • Optical fiber
  • Orbital
  • Operator
  • Oscillator
  • Overtones
  • Oxidation
  • Oersted
  • Oscillatory motion
  • Occam’s razor
  • Optical density
  • Ohmic conductor
  • Out-of-phase
  • Osmosis

Chemistry Words That Start With O:

  • Oxidation
  • Organic
  • Oxidizing agent
  • Oxidation state
  • Octet rule
  • Oxygen
  • Orbital
  • Organic chemistry
  • Oxide
  • Optical isomerism
  • Oxidative stress
  • Ozone
  • Olefin
  • Orthogonal
  • Oxime
  • Oxaloacetate
  • Optical activity
  • Ozonolysis
  • Osmolarity
  • Oligomer

Biology Words That Start With O:

  • Organism
  • Osmosis
  • Organelle
  • Oxygen
  • Ovary
  • Osteoblast
  • Oogenesis
  • Optic nerve
  • Olfactory
  • Organ system
  • Osmoregulation
  • Oviparous
  • Oviduct
  • Olfactory bulb
  • Ovulation
  • Operon
  • Osteoclast
  • Oxytocin
  • Orthologous genes
  • Olfactory receptor

Math Words That Start With O:

  • Operation
  • Operator
  • Order
  • Orthogonal
  • Outcome
  • Odds
  • Octagon
  • Octave
  • Ordinal
  • Origin
  • Odd number
  • One-to-one
  • Observational data
  • Open set
  • Orthocenter
  • Orthogonality
  • Onto
  • Oscillatory
  • Octahedron
  • Overlapping circles

Physical Science Words That Start With O:

  • Ohm’s law
  • Oscillation
  • Osmosis
  • Optics
  • Oxygen
  • Ozone
  • Ohmic conductor
  • Orbit
  • Observational study
  • Oort cloud

Science Words Beginning with O with Meaning:

  • Oxygen: Chemical element with the symbol O and atomic number 8.
  • Ozone: Triatomic form of oxygen, protecting Earth’s atmosphere.
  • Organism: Living individual, capable of carrying out life processes.
  • Oceanography: Study of the Earth’s oceans, their properties, and phenomena.
  • Orbit: Path followed by an object around another due to gravity.
  • Optics: Study of light and its behavior.
  • Oscillation: Back-and-forth motion around a central point.
  • Ontogeny: Individual development from embryo to adult.
  • Omnivore: Animal that consumes both plants and animals.
  • Organ: Structurally distinct part of a living organism with a specific function.
  • Overpopulation: Excessive population in relation to available resources.
  • Olfaction: Sense of smell.
  • Oblique: Not perpendicular or parallel, slanting or sloping.
  • Osmosis: Diffusion of solvent molecules through a semipermeable membrane.
  • Optimum: Best or most favorable condition or degree.
  • Outcrop: Exposed section of rock on the Earth’s surface.
  • Overfishing: Depletion of fish populations beyond their ability to reproduce.
  • Ozone layer: Region of Earth’s stratosphere with high ozone concentration.
  • Organism: Living individual, capable of carrying out life processes.
  • Outlier: Data point differing significantly from other observations.

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