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English Words Starting With F

5,868 entries — pick a word to see its definition, pronunciation, and usage.

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Noun Verb Adjective Adverb Plural noun Combining form Verb (transitive)Verb (intransitive)Verb (ambitransitive)

fission bomb
nounC2
/ˈfɪʃ(ə)n bɒm/A nuclear weapon that derives its destructive force from nuclear fission.
fission product
nounC2
/ˈfɪʃ(ə)n ˌprɒdʌkt/Any of the various atoms, usually radioactive, that result from the splitting of a heavy atomic nucleus during nuclear fission.
fission reactor
nounC2
/ˈfɪʃ.ən riˈæk.tər/A device or structure in which a controlled nuclear fission chain reaction is maintained to generate heat for power production or for creating radioactive isotopes.
fission-fusion bomb
nounLow
/ˈfɪʃn̩ ˈfjuːʒn̩ bɒm/A type of nuclear weapon that uses both nuclear fission and nuclear fusion reactions to produce an extremely powerful explosion, also known as a hydrogen bomb or thermonuclear bomb.
fission-track dating
nounVery low
/ˌfɪʃən træk ˈdeɪtɪŋ/A radiometric dating technique that uses the microscopic damage tracks (fission tracks) left in minerals by spontaneous fission of uranium-238 to determine the age of geological materials.
fissiped
adjectivenounVery Low (Specialist/Scientific)
/ˈfɪsɪpɛd/An animal whose toes are separated or divided; specifically, a member of the former mammalian order Fissipedia, which includes terrestrial carnivores like cats, dogs, and bears.
fissure
nounverbverb-intransitive+1C1
/ˈfɪʃ.ər/A long, narrow opening or crack, typically resulting from splitting or separation.
fissure eruption
nounC2
/ˈfɪʃə ɪˌrʌpʃən/A type of volcanic eruption where lava erupts from a long, linear crack in the Earth's surface, rather than from a central vent.
fissure of rolando
nounVery low
/ˌfɪʃər əv rəˈlændəʊ/A prominent groove in the brain's cerebral cortex that separates the frontal lobe from the parietal lobe.
fissure of sylvius
nounVery Low
/ˈfɪʃər əv ˈsɪlvɪəs/A deep, anatomical groove in each cerebral hemisphere that separates the frontal and parietal lobes from the temporal lobe.
fist
nounverbverb-transitiveB1
/fɪst/A hand with the fingers tightly curled inward toward the palm, typically for hitting or as a gesture of aggression or solidarity.
fist bump
nounMedium
/ˈfɪst ˌbʌmp/A gesture of greeting, celebration, or agreement in which two people lightly tap their closed fists together.
fist pump
nounB2
/ˈfɪst ˌpʌmp/A celebratory gesture where a person clenches their hand into a fist and thrusts it forward or upward, typically to express triumph, success, or excitement.
fistfight
nounB2
/ˈfɪst.faɪt/A physical fight between two or more people using their fists (closed hands) to punch each other.
fistful
nounC1
/ˈfɪstfʊl/an amount that can be held in a clenched hand.
fistiana
nounRare
/fɪstiˈɑːnə/Items or literature relating to boxing or pugilism.
fisticuff
nounverb-ambitransitiveLow
/ˈfɪstɪkʌf/A fistfight or a blow struck with the fist; a physical fight, often brief and disorderly.
fisticuffs
plural-nounLow
/ˈfɪstɪkʌfs/fighting with the fists; hand-to-hand fighting, especially as a form of combat or brawling.
fistmele
nounVery Low (Obscure/Historical)
/ˈfɪstˌmiːl/The proper distance between the archer's hand grip and the bowstring when the bow is strung and at rest; specifically, about seven inches or the width of a clenched fist with the thumb extended.
fistnote
nounC2/Rare
/ˈfɪstˌnəʊt/A short, forceful, or emphatic handwritten comment or annotation, typically made by clenching the writing instrument tightly, often expressing strong opinion, correction, or urgency.

Showing 2381–2400 of 5868 words.