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English Words Starting With A

8,734 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)

alpha emitter
nounVery Low (specialist term)
/ˈælfə ɪˌmɪtə/A radioactive substance that decays by emitting alpha particles.
alpha geek
nounLow
/ˌæl.fə ˈɡiːk/The most technically proficient person in a group or workplace.
alpha globulin
nounC2 / Very Rare / Technical
/ˌælfə ˈɡlɒbjʊlɪn/A type of globulin protein, particularly one of the plasma proteins (e.g., alpha-1 antitrypsin) with alpha electrophoretic mobility, part of the immune and transport systems in the blood.
alpha helix
nounRare / Very low (C2+ technical)
/ˌælfə ˈhiːlɪks/A common structural motif in proteins, where a single polypeptide chain twists into a right-handed spiral or helix, stabilized by hydrogen bonds.
alpha iron
nounC2
/ˈælfə ˈaɪən/A non-magnetic, body-centered cubic form of pure iron that is stable at low temperatures (below 912°C).
alpha male
nounC1
/ˌælfə ˈmeɪl/A man who takes a dominant, assertive, or leading role in a social or professional group.
alpha particle
nounC2
/ˈælfə ˌpɑːtɪkl̩/A type of subatomic particle consisting of two protons and two neutrons, identical to a helium-4 nucleus.
alpha privative
nounC2 (Very Low)
/ˌælfə prɪˈveɪtɪv/A prefix (from Greek a- or an-) meaning 'not', 'without', or 'lacking', used to form words that denote absence.
alpha radiation
nounC1
/ˈælfə ˌreɪdiˈeɪʃən/A type of ionizing radiation consisting of fast-moving, positively charged helium nuclei (two protons and two neutrons).
alpha ray
nounC1
/ˈælfə reɪ/A stream of alpha particles (helium nuclei) emitted by radioactive substances.
alpha receptor
nounC2/Technical
/ˈælfə rɪˈsɛptə/A type of cell-surface receptor in the sympathetic nervous system that responds to the neurotransmitter noradrenaline (norepinephrine), classified as either alpha-1 or alpha-2.
alpha rhythm
nounC2
/ˈælfə ˌrɪðəm/A pattern of regular electrical brain waves, typically between 8-12 Hz, associated with a relaxed, awake state with closed eyes.
alpha stock
nounLow in everyday language, medium in business and finance contexts.
/ˈælfə stɒk/A stock expected to outperform the market or generate excess returns on a risk-adjusted basis.
alpha test
nounverbMedium
/ˈælfə ˌtɛst/An initial internal test of a product, especially software, conducted by the developer's own team before release to external testers.
alpha-beta brass
nounC2 / Highly Technical / Professional Jargon
/ˌælfə ˈbiːtə brɑːs/A specific type of brass alloy containing both the alpha phase (copper-rich solid solution with face-centered cubic structure) and the beta phase (a harder, zinc-richer body-centered cubic structure), resulting in a two-phase microstructure.
alpha-fetoprotein
nounRare
/ˌælfə ˌfiːtəʊˈprəʊtiːn/A protein produced by the liver and yolk sac of a developing fetus, present in amniotic fluid and maternal blood.
alpha-hydroxy acid
nounC2 / Very Low Frequency / Domain-Specific
/ˌælfə haɪˌdrɒksɪ ˈæsɪd/A type of chemical compound that occurs naturally in fruit and milk, used in cosmetics and dermatology to exfoliate the skin.
alpha-ketoglutaric acid
nounC2/Highly Specialized
/ˌælfə ˌkiːtəʊɡluːˈtærɪk ˈæsɪd/A key intermediate compound in the Krebs cycle (citric acid cycle) of cellular respiration, involved in energy production and amino acid metabolism.
alpha-linolenic acid
nounLow
/ˌælfə lɪnəˈlɛnɪk ˈæsɪd/An essential omega-3 fatty acid found in plants, necessary for human health.
alpha-naphthylthiourea
nounVery Rare / Technical
/ˌalfə ˌnafθɪlˌθaɪəʊˈjuːriə/A specific chemical compound, formerly used as a potent rodenticide, known for its high toxicity.

Showing 3501–3520 of 8734 words.