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1. Abyss – From Greek ἄβυσσος (ábyssos), meaning “bottomless” or “unfathomable”.
2. Academy – From Greek Ἀκαδήμεια (Akadḗmeia), the grove near Athens where Plato taught.
3. Acoustic – From Greek ἀκουστικός (akoustikós), meaning “relating to hearing”.
4. Acrobatics – From Greek ἀκροβάτης (akrobátēs), “one who walks on tiptoe or at a height”, from ἄκρος (ákros) and βαίνειν (baínein).
5. Acromegaly – From Greek ἄκρον (ákron), “extremity”, and μέγας (mégas), “large”.
6. Acronym – Formed from Greek ἄκρος (ákros), “outermost” or “extreme”, and ὄνομα (ónoma), “name”.
7. Acrophobia – From Greek ἄκρος (ákros), “high”, and φόβος (phóbos), “fear”.
8. Acropolis – From Greek ἀκρόπολις (akrópolis), “upper city”, from ἄκρος (ákros) and πόλις (pólis).
9. Aerial – Through Latin from Greek ἀέριος (aérios), “of the air”, from ἀήρ (aḗr), “air”.
10. Aerodynamic – Formed from Greek ἀήρ (aḗr), “air”, and δύναμις (dýnamis), “power” or “force”.
11. Aesthetics – From Greek αἰσθητικός (aisthētikós), “relating to perception”, from αἴσθησις (aísthēsis), “perception” or “sensation”.
12. Agape – From Greek ἀγάπη (agápē), meaning “love” or “affection”.
13. Agnostic – From Greek ἄγνωστος (ágnōstos), meaning “unknown” or “unknowable”, from ἀ- (a-), “not”, and γνωστός (gnōstós), “known”.
14. Agony – From Greek ἀγωνία (agōnía), originally “contest”, “struggle” or “anguish”.
15. Agora – From Greek ἀγορά (agorá), meaning “assembly”, “marketplace” or “public gathering place”.
16. Agoraphobia – From Greek ἀγορά (agorá), “marketplace” or “public place”, and φόβος (phóbos), “fear”.
17. Air – Through Latin and French from Greek ἀήρ (aḗr), meaning “air” or “lower atmosphere”.
18. Algorithm – From the Latinised name of the Persian mathematician al-Khwarizmi; the later spelling was influenced by Greek ἀριθμός (arithmós), “number”.
19. Allegory – From Greek ἀλληγορία (allēgoría), meaning figurative speech in which one thing is expressed through another.
20. Alphabet – From the Greek letter names ἄλφα (álpha) and βῆτα (bêta), the first two letters of the Greek alphabet.
21. Ambrosia – From Greek ἀμβροσία (ambrosía), “food of the immortals”, related to ἄμβροτος (ámbrotos), “immortal”.
22. Ammonia – Named through Latin sal ammoniacus, “salt of Ammon”, referring to the Egyptian god Amun, known in Greek as Ἄμμων (Ámmōn).
23. Amnesia – From Greek ἀμνησία (amnēsía), meaning “forgetfulness” or “loss of memory”.
24. Amnesty – From Greek ἀμνηστία (amnēstía), “forgetfulness of wrongs” or “pardon”.
25. Amphibious – From Greek ἀμφίβιος (amphíbios), “living a double life” or “living on both land and water”.
26. Amphitheatre – From Greek ἀμφιθέατρον (amphithéatron), a theatre with seating around or on both sides.
27. Amphora – From Greek ἀμφορεύς (amphoreús), a two-handled vessel, from an older form meaning “carried on both sides”.
28. Anachronism – From Greek ἀνά (aná) and χρόνος (khrónos), “time”; something placed in the wrong historical period.
29. Anaemia – From Greek ἀναιμία (anaimía), “lack of blood”, from ἀν- (an-), “without”, and αἷμα (haîma), “blood”.
30. Anaesthesia – From Greek ἀναισθησία (anaisthēsía), “lack of sensation”, from ἀν- (an-) and αἴσθησις (aísthēsis).
31. Anagram – From Greek ἀνά (aná), “again” or “back”, and γράμμα (grámma), “letter”.
32. Analogy – From Greek ἀναλογία (analogía), meaning “proportion” or “correspondence”.
33. Analysis – From Greek ἀνάλυσις (análysis), “a loosening” or “breaking up into parts”.
34. Anaphora – From Greek ἀναφορά (anaphorá), “a carrying back” or “reference”.
35. Anarchy – From Greek ἀναρχία (anarkhía), “absence of a ruler”, from ἀν- (an-) and ἀρχή (arkhḗ).
36. Anathema – From Greek ἀνάθεμα (anáthema), originally “something dedicated or set apart”, later something formally condemned.
37. Anatomy – From Greek ἀνατομή (anatomḗ), “dissection”, literally “cutting up”.
38. Android – From Greek ἀνδρ- (andr-), “man”, and -οειδής (-oeidḗs), “resembling” or “having the form of”.
39. Anecdotal – From Greek ἀνέκδοτος (anékdotos), “unpublished”, from ἀν- (an-) and ἐκδιδόναι (ekdidónai), “to publish”.
40. Angel – From Greek ἄγγελος (ángelos), meaning “messenger”.
41. Angiology – From Greek ἀγγεῖον (angeîon), “vessel”, and -λογία (-logía), “study”.
42. Anomaly – From Greek ἀνωμαλία (anōmalía), meaning “unevenness” or “irregularity”.
43. Anonymous – From Greek ἀνώνυμος (anṓnymos), meaning “without a name”, from ἀν- (an-) and ὄνομα (ónoma), “name”.
44. Antagonist – From Greek ἀνταγωνιστής (antagōnistḗs), meaning “opponent” or “competitor”.
45. Anthem – From Greek ἀντίφωνα (antíphōna), “responsive verses”, from ἀντί (antí) and φωνή (phōnḗ), “voice”.
46. Anthology – From Greek ἀνθολογία (anthología), literally “a collection of flowers”, later a collection of selected writings.
47. Anthropoid – From Greek ἄνθρωπος (ánthrōpos), “human being”, and -οειδής (-oeidḗs), “resembling”.
48. Anthropology – From Greek ἄνθρωπος (ánthrōpos), “human being”, and -λογία (-logía), “study”.
49. Antibiotic – From Greek ἀντί (antí), “against”, and βίος (bíos), “life”; coined for substances acting against microorganisms.
50. Antidote – From Greek ἀντίδοτον (antídoton), “something given against”, from ἀντί (antí) and διδόναι (didónai), “to give”.
51. Antipodes – From Greek ἀντίποδες (antípodes), literally “those with feet opposite”.
52. Antithesis – From Greek ἀντίθεσις (antíthesis), “opposition” or “placing against”.
53. Anxiety – From Greek ἄγχω (ánkhō), meaning “to choke”, “strangle” or “constrict”.
54. Apathy – From Greek ἀπάθεια (apátheia), originally “freedom from emotion or suffering”, from ἀ- (a-) and πάθος (páthos), “feeling” or “suffering”.
55. Aphasia – From Greek ἀφασία (aphasía), “speechlessness”, from ἀ- (a-) and φάσις (phásis), “speech”.
56. Aphorism – From Greek ἀφορισμός (aphorismós), “definition” or “concise statement”, from ἀφορίζειν (aphorízein), “to mark off or define”.
57. Aphrodisiac – From Greek ἀφροδισιακός (aphrodisiakós), “relating to sexual desire”, from Ἀφροδίτη (Aphrodítē), Aphrodite.
58. Apocalypse – From Greek ἀποκάλυψις (apokálypsis), meaning “uncovering” or “revelation”.
59. Apocrypha – From Greek ἀπόκρυφος (apókryphos), meaning “hidden” or “secret”.
60. Apology – From Greek ἀπολογία (apología), originally “a speech in defence”; the sense “expression of regret” developed later.
61. Apostle – From Greek ἀπόστολος (apóstolos), meaning “one who is sent out” or “messenger”.
62. Apostrophe – From Greek ἀποστροφή (apostrophḗ), “a turning away”, from ἀποστρέφειν (apostréphein).
63. Apothecary – From Greek ἀποθήκη (apothḗkē), meaning “storehouse”.
64. Apothegm – From Greek ἀπόφθεγμα (apóphthegma), meaning a concise, memorable saying.
65. Apotheosis – From Greek ἀποθέωσις (apothéōsis), meaning “deification” or “making into a god”.
66. Arachnophobia – From Greek ἀράχνη (arákhnē), “spider”, and φόβος (phóbos), “fear”.
67. Archaeology – From Greek ἀρχαῖος (arkhaîos), “ancient”, and -λογία (-logía), “study”.
68. Archetype – From Greek ἀρχέτυπον (arkhétypon), “original pattern”, from ἀρχή (arkhḗ) and τύπος (týpos).
69. Archipelago – Through Italian arcipelago, originally a name for the Aegean Sea, with Greek πέλαγος (pélagos), “open sea”.
70. Architecture – From Greek ἀρχιτέκτων (arkhitéktōn), “master builder”, from ἀρχι- (arkhi-) and τέκτων (téktōn).
71. Archive – From Greek ἀρχεῖον (arkheîon), a public building or government office where official records were kept.
72. Aristocracy – From Greek ἀριστοκρατία (aristokratía), “rule by the best”, from ἄριστος (áristos), “best”, and κράτος (krátos), “power” or “rule”.
73. Arithmetic – From Greek ἀριθμητική (arithmētikḗ), “the art of counting”, from ἀριθμός (arithmós), “number”.
74. Aroma – From Greek ἄρωμα (árōma), meaning “spice”, “seasoning” or “fragrant substance”.
75. Article – From Greek ἄρθρον (árthron), meaning “joint”, “articulation” or a distinct part of a whole.
76. Aseptic – From Greek ἀ- (a-), “without”, and σηπτικός (sēptikós), “causing putrefaction”.
77. Asterisk – From Greek ἀστερίσκος (asterískos), “little star”, from ἀστήρ (astḗr), “star”.
78. Asteroid – Formed from Greek ἀστήρ (astḗr), “star”, and -οειδής (-oeidḗs), “resembling” or “having the form of”.
79. Asthma – From Greek ἆσθμα (âsthma), meaning “panting” or “short-drawn breath”.
80. Astigmatism – Formed from Greek ἀ- (a-), “without”, and στίγμα (stígma), “mark” or “point”.
81. Astraphobia – From Greek ἀστραπή (astrapḗ), “lightning”, and φόβος (phóbos), “fear”.
82. Astrology – From Greek ἀστρολογία (astrología), “study or account of the stars”.
83. Astronaut – Formed from Greek ἄστρον (ástron), “star”, and ναύτης (naútēs), “sailor”.
84. Astronomy – From Greek ἀστρονομία (astronomía), from ἄστρον (ástron), “star”, and νόμος (nómos), “law” or “arrangement”.
85. Astrophysics – Formed from Greek ἄστρον (ástron), “star”, and φυσική (physikḗ), “the study of nature”.
86. Asylum – From Greek ἄσυλον (ásylon), “inviolable place” or “refuge”, from ἄσυλος (ásylos), “safe from seizure”.
87. Asymmetry – From Greek ἀσυμμετρία (asymmetría), “lack of proportion or symmetry”.
88. Asynchronous – From Greek ἀ- (a-), “not”, and σύγχρονος (sýnkhronos), “occurring at the same time”.
89. Atheism – From Greek ἄθεος (átheos), “without a god” or “godless”.
90. Athlete – From Greek ἀθλητής (athlētḗs), meaning “contestant” or “competitor for a prize”.
91. Athletic – From Greek ἀθλητικός (athlētikós), “relating to contests or athletes”.
92. Athlon – From Greek ἆθλον (âthlon), meaning “prize of a contest” or “contest”; found in words such as decathlon and triathlon.
93. Atlas – From Greek Ἄτλας (Átlas), the mythological figure who supported the heavens; the map-book sense developed later.
94. Atmosphere – From Greek ἀτμός (atmós), “vapour”, and σφαῖρα (sphaîra), “sphere”.
95. Atom – From Greek ἄτομος (átomos), “uncuttable” or “indivisible”, from ἀ- (a-) and τέμνειν (témnein), “to cut”.
96. Atrophy – From Greek ἀτροφία (atrophía), meaning “lack of nourishment” or “wasting away”.
97. Aura – From Greek αὔρα (aúra), meaning “breeze” or “breath”.
98. Autarchy – From Greek αὐταρχία (autarkhía), “absolute rule by oneself”; it should not be confused with autarky, “self-sufficiency”.
99. Authentic – From Greek αὐθεντικός (authentikós), originally “authoritative” or “acting on one’s own authority”, later “genuine”.
100. Autism – Formed from Greek αὐτός (autós), meaning “self”.
101. Autobiography – Formed from Greek αὐτός (autós), “self”, βίος (bíos), “life”, and γραφή (graphḗ), “writing”.
102. Autocrat – From Greek αὐτοκράτωρ (autokrátōr), “one who rules by oneself”, from αὐτός (autós) and κράτος (krátos).
103. Autodidact – From Greek αὐτοδίδακτος (autodídaktos), “self-taught”.
104. Automatic – From Greek αὐτόματος (autómatos), “self-moving” or “acting of oneself”.
105. Automobile – Formed from Greek αὐτός (autós), “self”, and Latin mobilis, “movable”.
106. Autonomy – From Greek αὐτονομία (autonomía), “self-government”, from αὐτός (autós) and νόμος (nómos), “law”.
107. Autopsy – From Greek αὐτοψία (autopsía), “seeing with one’s own eyes”, from αὐτός (autós) and ὄψις (ópsis).
108. Axial – From Greek ἄξων (áxōn), meaning “axle” or “axis”; relating to or forming an axis.
109. Axiom – From Greek ἀξίωμα (axíōma), “that which is considered worthy or accepted”, later a self-evident principle.
110. Axis – From Greek ἄξων (áxōn), meaning “axle” or “axis”.
111. Axon – From Greek ἄξων (áxōn), “axis” or “axle”.
112. Azoic – From Greek ἀ- (a-), “without”, and ζωή (zōḗ), “life”.
113. Azotaemia – From French azote, “nitrogen”, coined from Greek ἀ- (a-), “without”, and ζωή (zōḗ), “life”, plus -aemia from αἷμα (haîma), “blood”.