A
- Abyss – From Abyssos, (bottomless)
- Academy – From ‘Akademia’, Plato’s school of philosophy.
- Acoustic – From ‘akoustikos’, pertaining to hearing.
- Acrobatics – From ‘akro’ meaning high, and bainein “to walk”
- Acromegaly – From ‘akro’ meaning ‘tip’ and ‘megalos’ meaning ‘large’
- Acronym – From “akros,” meaning “topmost” or “extreme,” and “onym,” from “onoma,” meaning “name.
- Acrophobia – From ‘Akro” meaning high and phobia (fear)
- Acropolis – From “Akro” meaning high and polis (city)
- Aerial – From ‘aeras” meaning (air)
- Aerodynamic – From ‘Aeras’ (air) and ‘dynami’ (power)
- Aesthetics – From Aisthitikos (sensitive or perspective)
- Agape – From Agape (love)
- Agony – From agonia
- Agora – From Agora
- Agoraphobia – From “agora’ meaning assembly and ‘phobia’ fear
- Air – From ‘aeras”
- Algorithm – From ‘arithmos’, meaning number.
- Ambrosia – From ‘a-‘ and brotos (mortal)
- Ammonia – From Ammon the Egyptian God
- Amnesty – A- (non) and mnaisthai (to remember)
- Amphibious – From ‘amphibios’ meaning leaving two lifes
- Amphitheatre – From Amfitheatron
- Amphora – From amphi- (both) and ferein (to carry)
- Anaemia – From ‘anaimia’, lack of blood.
- Anaesthesia – From ‘an’ (without) and ‘aisthesis’ (sensation).
- Anagram – From ana- and gramma (letter)
- Anachronism – From ana- and chronos (time)
- Analogy – From ‘analogia’, proportion.
- Analysis – From ‘analysis’, meaning the untie
- Anaphora – From ‘anaphora’ (reference)
- Anarchy – From ‘anarchia’, without a ruler.
- Anathema – From anathema (excommunication)
- Anatomy – From ‘anatome’, dissection.
- Android – From “andras”, male.
- Anecdotal – From anekdotos (unpublished)
- Angel – From ‘aggelos’ messenger
- Angiology – From ‘angeion’ (vessel) and ‘logia’ (study of).
- Anomaly – From anomalia unevenness
- Antagonist – From ‘antagonistes” meaning opponents, rivals etc
- Anthem – From antiphonon
- Anthology – From ‘anthos’ (flower) and ‘legein’ (to gather).
- Anthropoid – From ‘anthropos” (human)
- Anthropology – From ‘anthropos’ (human) and ‘logia’.
- Antibiotic – From ‘anti’ (against) and ‘bios’ (life).
- Antidote – From ‘anti’ and ‘didonai’ to give.
- Antipodes – From ‘anti’ (against) and ‘podi’ (foot)
- Antithesis – From ‘anti’ (against) and ‘thesis” (place).
- Anxiety – From agkho (to choke)
- Aphasia – From afasia
- Aphorism – From aphorismos (to delimit)
- Apocalypse – From ‘apokalupsis’, revelation.
- Apocrypha – From ‘apokryphos’, hidden.
- Apology – From ‘apologia’ (confession)
- Apostrophe – From ‘apostrephein’, turning away.
- Apothecary – From ‘apotheke” , storehouse
- Apotheosis – From ‘apotheosis” deification
- Arachnophobia – From ‘arachne’ (spider) and phobia( fear)
- Archaeology – From ‘archaios’, ancient.
- Archetype – From ‘archetypo’
- Achipelago – From ‘arche” chief and pelagos (sea)
- Architecture – From ‘arkhitekton’, master builder.
- Archive – From αρχείο (archive)
- Arithmetic – From ‘arithmos’, number.
- Article – From ‘άρθρο’
- Aroma – from ‘aroma” (scent)
- Aseptic – From ‘a’ (without) and ‘septicos’ (putrefactive).
- Asterisk – From ‘asteriskos’, little star.
- Astigmatism – From ‘a’ (without) and ‘stigma’ (point).
- Astraphobia – From ‘astrapē’ (lightning) and ‘phobia’ (fear).
- Astrology – From ‘astron’, star and logos (study)
- Astronaut – From ‘astron’, star and ‘nautes” (sailor)
- Astronomy – From ‘astron’, star and nomos (law)
- Astrophysics – From ‘astron’ star and physika (nature)
- Asylum – From asylon
- Asymmetry – From ‘a’ (without) and ‘symmetria’ (symmetry).
- Asynchronous – From ‘a’ (without) and synchronos (same time).
- Asthma – From ‘asthma’, panting.
- Atheism – From ‘atheos’, without god.
- Athletic – From ‘athletikos”
- Atlas – From Atlas
- Atmosphere – From ‘atmos’, vapor.
- Atom – From “atomos” indivisible
- Autarchy – From ‘autarkhia’, self-sufficiency.
- Authentic – From ‘authentikos’, original
- Autobiography – From ‘autos’, self.
- Autocrat -From autokratoras
- Autodidact – From “autos” (self), didact didasko (to teach)
- Automatic – From “automatos”
- Automobile – From ‘autos’ and ‘mobilis’, movable.
- Autonomy – From ‘autonomia’, self-law.
- Autopsy – “auto” meaning “self” and “opsis” meaning “sight,”
- Axial – From ‘axios’, worth.
- Axiom – From ‘axioma’, that which is thought fitting.
- Axis – From ‘axōn’, axle.
- Axon – From ‘axōn’, axis.
- Azoic – From ‘a’ (without) and ‘zoē’ (life).
- Azotemia – From ‘azote’ (nitrogen) and ‘haima’ (blood).