This list includes 53 Earth science words that start with E, from “E horizon” to “Exsolution”. They cover terms across geology, soil science, meteorology, and oceanography. You will find these words in classrooms, fieldwork notes, and environmental research.

Earth science words that start with E are the specialized terms used to describe Earth’s materials, processes, and features. Many have Latin or Greek roots, and some entered common use through early naturalists’ field reports.

Below you’ll find the table with term, definition, category, and further reading.

Term: The word or phrase itself, so you can quickly scan the list and locate specific entries.

Definition: A concise 1–2 sentence explanation that gives you clear meaning and practical context.

Category: A short label indicating the subfield or theme, helping you compare related terms at a glance.

Further reading: Links to articles or resources where you can explore each term more deeply and see examples.

Earth science words that start with E

Term Subfield Category/Type Common units or typical scale Description
Earth other Other radius: 6,371 km; age: 4.54 billion years Our planet, the integrated system of atmosphere, hydrosphere, lithosphere and biosphere studied by Earth scientists.
Earthquake seismology Process magnitude: 0–9+; depth: 0–700 km Sudden shaking of the ground caused by rapid release of energy along faults or volcanic activity, measured by magnitude and felt as seismic waves.
Epicenter seismology Other distance: km from epicenter The point on Earth’s surface directly above an earthquake’s focus, used to locate and describe earthquake impacts.
Eon geology Concept duration: hundreds of millions to billions of years The largest division of geologic time, grouping eras and epochs into very long intervals like the Phanerozoic or Archean.
Era geology Concept duration: tens to hundreds of millions of years A major subdivision of an eon, such as the Mesozoic, used to organize Earth’s long-term history.
Epoch geology Concept duration: thousands to millions of years A subdivision of a geologic period, like the Holocene; used to describe shorter intervals in Earth’s history.
Erosion geomorphology Process rates: mm to m per year depending on setting The wearing away and removal of soil and rock by water, wind, ice or gravity, shaping landscapes over time.
Eolian geomorphology Process dune sizes: meters to hundreds of meters Relating to wind-driven processes, including erosion, transport, and deposition of sand and dust.
Esker glaciology Landform length: 100 m to tens of km; height: meters to tens of meters A long, winding ridge of sand and gravel deposited by meltwater streams flowing beneath glaciers.
Estuary oceanography Landform depth: a few m to tens of m; length: km to hundreds of km A coastal area where river freshwater mixes with ocean saltwater, supporting rich ecosystems and variable salinity.
Evaporation hydrology Process rates: 0–10 mm/day typical; temperature-driven The conversion of liquid water to vapor at a surface, a key step in the water cycle and energy exchange.
Evapotranspiration hydrology Measurement units: mm/day or mm/yr; annual: 0–2,000 mm/yr Combined water loss from evaporation and plant transpiration, used in water-budget and crop studies.
Evaporite sedimentary geology Rock/Mineral deposit thickness: cm to 100s m Sedimentary rocks formed by precipitation of salts from evaporating water, including halite and gypsum.
Eclogite petrology Rock/Mineral forms at high pressure: tens of km depth A dense, high-pressure metamorphic rock commonly formed in subduction zones and recognized by garnet and omphacite.
Ejecta volcanology Other deposit thickness: mm to tens of meters Material thrown out during an impact or volcanic eruption that falls back and forms deposits around the source.
Effusive eruption volcanology Process lava flow length: meters to tens of km; duration: days to years A volcanic eruption dominated by flowing lava rather than explosive ash, producing lava flows and shields.
Explosive eruption volcanology Process VEI: 0–8; plume height: meters to tens of km A violent volcanic event that fragments magma into ash and tephra, often producing high eruption columns and widespread ashfall.
Exsolution geochemistry Process temperature: hundreds to over 1,000 °C in magmas Separation of a mineral or fluid phase from a cooling magma or solid solution, forming separate mineral phases.
Exhumation geology Process uplift/exposure: kilometers; timescale: thousands to millions of years The process by which buried rocks are brought to Earth’s surface by uplift and erosion.
El Niño oceanography Climate/Ocean/Atmosphere Phenomenon periodicity: 2–7 years; SST anomaly: +0.5–2.5 °C A warm phase of the tropical Pacific climate pattern that alters global weather, ocean conditions and rainfall.
El Niño–Southern Oscillation climatology Climate/Ocean/Atmosphere Phenomenon cycle: 2–7 years; impacts: global The coupled ocean–atmosphere phenomenon (El Niño and La Niña) that drives large-scale climate variability worldwide.
Ekman transport oceanography Process depth: tens of meters; horizontal scale: 10s km Wind-driven surface water transport caused by Earth’s rotation, producing net water movement at right angles to wind direction.
Eddy oceanography Climate/Ocean/Atmosphere Phenomenon diameter: tens to hundreds of km; lifetime: days to months A swirling ocean or atmospheric circulation feature that redistributes heat, nutrients and momentum.
Epeirogeny geophysics Process uplift/subsidence: mm to cm/yr; regional scale: continental Slow, broad vertical motions of Earth’s crust producing gentle uplift or subsidence across continents.
Elastic rebound seismology Concept fault slip: mm to meters A theory describing how elastic strain accumulates on faults and is suddenly released as earthquakes when rock snaps back.
Electrical conductivity geophysics Measurement units: S/m; crustal ranges vary widely A measure of how easily materials conduct electric current, used to infer underground fluids and rock types.
Eluvial deposit soil soil thickness: cm to meters Material concentrated in a soil layer by leaching and removal of finer particles, often overlying a B horizon.
E horizon soil Other thickness: a few cm to 1 m A leached, light-colored soil layer found beneath the O or A horizons, common in forest soils.
End moraine glaciology Landform height: meters to hundreds of meters; length: km A ridge of till deposited at the edge of a glacier, marking a former glacier terminus.
Endorheic basin hydrology Landform area: km² to hundreds of thousands km² A drainage basin that retains water with no outflow to the ocean, often forming saline lakes or playas.
Equilibrium line altitude glaciology Measurement altitude: sea level to >5,000 m The glacier elevation where annual accumulation equals ablation, used to assess glacier health and climate.
Eustasy oceanography Concept sea-level change: mm/yr to 100s m over glacial cycles Global changes in sea level caused by variations in ocean volume or ice-sheet volume, not local tectonics.
Eustatic sea level oceanography Measurement change range: mm/yr (modern) to 100+ m (glacial cycles) The global average sea level, influenced by ice volume and ocean water volume.
Evaporation pan hydrology Instrument measures: mm/day evaporation A shallow pan used to measure open-water evaporation rates for estimating local evapotranspiration.
Energy balance climatology Concept units: W/m²; solar incoming ~340 W/m² globally Accounting of incoming and outgoing energy at Earth’s surface or atmosphere that controls climate and temperature.
Equator climatology Other latitude: 0°; circumference: 40,075 km The imaginary line around Earth equidistant from the poles, dividing the Northern and Southern Hemispheres.
Equinox climatology Climate/Ocean/Atmosphere Phenomenon dates: ~Mar 20, Sep 23; day/night roughly equal Times of year when the Sun crosses the equator, producing nearly equal day and night lengths worldwide.
Equatorial current oceanography Climate/Ocean/Atmosphere Phenomenon speed: ~0.1 m/s typical; width: 10s to 100s km Major ocean currents flowing westward along the equator that transport heat and influence climate.
Evaporative cooling climatology Process temperature drop: a few °C locally Cooling that occurs when evaporation removes heat from a surface, important for cloud and boundary-layer processes.
Entrainment meteorology Process units: often quantified in m/s or Pa shear The process by which ambient fluid is drawn into a flow, such as air into clouds or sediment into water currents.
Equifinality geomorphology Concept scale: process to landscape The idea that different processes or histories can produce similar landscape forms, complicating interpretation.
Escarpment geomorphology Landform height: meters to thousands of meters; length: km to 1,000s km A steep slope or long cliff formed by faulting or erosion that separates two relatively level areas.
Enstatite mineralogy Rock/Mineral common in mafic rocks; crystal mm–cm A magnesium-rich pyroxene mineral found in igneous and some meteorite rocks, important in petrology.
Epidote mineralogy Rock/Mineral crystal size: mm to cm; common in metamorphics A green silicate mineral typical of low- to medium-grade metamorphism and hydrothermal alteration.
Eolianite sedimentary geology Rock/Mineral thickness: meters to tens of meters A lithified rock formed from cemented wind-blown (aeolian) sand, usually coastal or desert in origin.
Endmember geochemistry Concept compositional end points in mixing models A pure component or theoretical composition used to describe mixing and source contributions in geochemistry.
Empirical orthogonal function (EOF) climatology Concept used on datasets: time series and maps A statistical method that identifies dominant patterns of variability in climate or oceanographic data.
Eruption volcanology Process lava/ash output: kg to km³; duration: minutes to years The release of magma, gases and ash from a volcano, ranging from gentle lava flows to explosive blasts.
Eruption plume volcanology Climate/Ocean/Atmosphere Phenomenon height: hundreds of meters to >40 km; ash spread: local to global A column of ash, gas and aerosols rising from an explosive eruption that can affect air travel and climate.
Earth tide geophysics Phenomenon vertical displacement: mm to tens of cm Small deformations of Earth’s crust caused by gravitational pulls of the Moon and Sun, measurable by sensitive instruments.
Earth’s core geophysics Other radius: inner core ~1,220 km; outer core ~2,260 km The dense, metal-rich central part of Earth, generating the planet’s magnetic field through convecting liquid iron.
Earth’s mantle geophysics Other thickness: ~2,900 km The solid but slowly flowing layer between the crust and core that drives plate tectonics and mantle convection.
Earthquake early warning seismology Instrument lead time: seconds to minutes Systems that detect initial earthquake waves to send warnings before strong shaking arrives, reducing harm and damage.

Descriptions

Earth
Earthquake
Epicenter
Eon
Era
Epoch
Erosion
Eolian
Esker
Estuary
Evaporation
Evapotranspiration
Evaporite
Eclogite
Ejecta
Effusive eruption
Explosive eruption
Exsolution
Exhumation
El Niño
El Niño–Southern Oscillation
Ekman transport
Eddy
Epeirogeny
Elastic rebound
Electrical conductivity
Eluvial deposit
E horizon
End moraine
Endorheic basin
Equilibrium line altitude
Eustasy
Eustatic sea level
Evaporation pan
Energy balance
Equator
Equinox
Equatorial current
Evaporative cooling
Entrainment
Equifinality
Escarpment
Enstatite
Epidote
Eolianite
Endmember
Empirical orthogonal function (EOF)
Eruption
Eruption plume
Earth tide
Earth’s core
Earth’s mantle
Earthquake early warning
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