The name Apollo—unlike the related older name Paean—is generally not found in the Linear B (Mycenean Greek) texts, although there is a possible attestation in the lacunose form ]pe-rjo-[ (Linear B: ]𐀟𐁊-[) on the KN E 842 tablet.
The etymology of the name is uncertain. The spelling Ἀπόλλων (pronounced [a.pól.lɔːn] in Classical Attic) had almost superseded all other forms by the beginning of the common era, but the Doric form, Apellon (Ἀπέλλων), is more archaic, as it is derived from an earlier *Ἀπέλjων. It probably is a cognate to the Doric month Apellaios (Ἀπελλαῖος), and the offerings apellaia (ἀπελλαῖα) at the initiation of the young men during the family-festival apellai (ἀπέλλαι).
According to some scholars, the words are derived from the Doric word apella (ἀπέλλα), which originally meant "wall," "fence for animals" and later "assembly within the limits of the square." Apella (Ἀπέλλα) is the name of the popular assembly in Sparta, corresponding to the ecclesia (ἐκκλησία). R. S. P. Beekes rejected the connection of the theonym with the noun apellai and suggested a Pre-Greek proto-form *Apalyun.
Several instances of popular etymology are attested from ancient authors. Thus, the Greeks most often associated Apollo's name with the Greek verb ἀπόλλυμι (apollymi), "to destroy". Plato in Cratylus connects the name with ἀπόλυσις (apolysis), "redemption", with ἀπόλουσις (apolousis), "purification", and with ἁπλοῦν ([h]aploun), "simple", in particular in reference to the Thessalian form of the name, Ἄπλουν, and finally with Ἀειβάλλων (aeiballon), "ever-shooting". Hesychius connects the name Apollo with the Doric ἀπέλλα (apella), which means "assembly", so that Apollo would be the god of political life, and he also gives the explanation σηκός (sekos), "fold", in which case Apollo would be the god of flocks and herds. In the ancient Macedonian language πέλλα (pella) means "stone," and some toponyms may be derived from this word: Πέλλα (Pella, the capital of ancient Macedonia) and Πελλήνη (Pellēnē/Pallene).
A number of non-Greek etymologies have been suggested for the name, The Hittite form Apaliunas (dx-ap-pa-li-u-na-aš) is attested in the Manapa-Tarhunta letter, perhaps related to Hurrian (and certainly the Etruscan) Aplu, a god of plague, in turn likely from Akkadian Aplu Enlil meaning simply "the son of Enlil", a title that was given to the god Nergal, who was linked to Shamash, Babylonian god of the sun.
The role of Apollo as god of plague is evident in the invocation of Apollo Smintheus ("mouse Apollo") by Chryses, the Trojan priest of Apollo, with the purpose of sending a plague against the Greeks (the reasoning behind a god of the plague becoming a god of healing is apotropaic, meaning that the god responsible for bringing the plague must be appeased in order to remove the plague).
The Hittite testimony reflects an early form *Apeljōn, which may also be surmised from comparison of Cypriot Ἀπείλων with Doric Ἀπέλλων. The name of the Lydian god Qλdãns /kʷʎðãns/ may reflect an earlier /kʷalyán-/ before palatalization, syncope, and the pre-Lydian sound change *y > d. Note the labiovelar in place of the labial /p/ found in pre-Doric Ἀπέλjων and Hittite Apaliunas.
A Luwian etymology suggested for Apaliunas makes Apollo "The One of Entrapment", perhaps in the sense of "Hunter".
Apollo's chief epithet was Phoebus (/ FEE-bəs; Φοῖβος, Phoibos Greek pronunciation: [pʰó͜i.bos]), literally "bright". It was very commonly used by both the Greeks and Romans for Apollo's role as the god of light. Like other Greek deities, he had a number of others applied to him, reflecting the variety of roles, duties, and aspects ascribed to the god. However, while Apollo has a great number of appellations in Greek myth, only a few occur in Latin literature.
- Aegletes (/ GLEE-teez; Αἰγλήτης, Aiglētēs), from αἴγλη, "light of the sun"
- Helius (/ HEE-lee-əs; Ἥλιος, Helios), literally "sun"
- Lyceus (/ SEE-əs; Λύκειος, Lykeios, from Proto-Greek *λύκη) "light". The meaning of the epithet "Lyceus" later became associated with Apollo's mother Leto, who was the patron goddess of Lycia (Λυκία) and who was identified with the wolf (λύκος).
- Phanaeus (/ NEE-əs; Φαναῖος, Phanaios), literally "giving or bringing light"
- Phoebus (/ FEE-bəs; Φοῖβος, Phoibos), literally "bright", his most commonly used epithet by both the Greeks and Romans
- Sol (Roman) (/ SOL), "sun" in Latin
- Lycegenes (/ SEJ-ə-neez; Λυκηγενής, Lukēgenēs), literally "born of a wolf" or "born of Lycia"
- Lycoctonus (/ KOK-tə-nəs; Λυκοκτόνος, Lykoktonos), from λύκος, "wolf", and κτείνειν, "to kill"
Origin and birth
Apollo's birthplace was Mount Cynthus on the island of Delos.
- Cynthius (/ SIN-thee-əs; Κύνθιος, Kunthios), literally "Cynthian"
- Cynthogenes (/ THOJ-i-neez; Κυνθογενής, Kynthogenēs), literally "born of Cynthus"
- Delius (/ DEE-lee-əs; Δήλιος, Delios), literally "Delian"
- Didymaeus (/ MEE-əs; Διδυμαῖος, Didymaios) from δίδυμος, "twin") as Artemis' twin
Partial view of the temple of Apollo Epikurios (healer) at Bassae
in southern Greece
Place of worship
Delphi and Actium were his primary places of worship.
- Acraephius (/ KREE-fee-əs; Ἀκραίφιος, Akraiphios, literally "Acraephian") or Acraephiaeus (/ EE-əs; Ἀκραιφιαίος, Akraiphiaios), "Acraephian", from the Boeotian town of Acraephia (Ἀκραιφία), reputedly founded by his son Acraepheus.
- Actiacus (/ TY-ə-kəs; Ἄκτιακός, Aktiakos), literally "Actian", after Actium (Ἄκτιον)
- Delphinius (/ FIN-ee-əs; Δελφίνιος, Delphinios), literally "Delphic", after Delphi (Δελφοί). An etiology in the Homeric Hymns associated this with dolphins.
- Pythius (/ PITH-ee-əs; Πύθιος, Puthios, from Πυθώ, Pythō), from the region around Delphi
- Smintheus (/ SMIN-thews; Σμινθεύς, Smintheus), "Sminthian"—that is, "of the town of Sminthos or Sminthe" near the Troad town of Hamaxitus
Temple of the Delians at Delos
, dedicated to Apollo (478 BC). 19th-century pen-and-wash restoration.
Temple of Apollo Smintheus at Çanakkale
Healing and disease
- Acesius (/ SEE-zhəs; Ἀκέσιος, Akesios), from ἄκεσις, "healing". Acesius was the epithet of Apollo worshipped in Elis, where he had a temple in the agora.
- Acestor (/ SES-tər; Ἀκέστωρ, Akestōr), literally "healer"
- Culicarius (Roman) (/ KARR-ee-əs), from Latin culicārius, "of midges"
- Iatrus (/ AT-rəs; Ἰατρός, Iātros), literally "physician"
- Medicus (Roman) (/ MED-i-kəs), "physician" in Latin. A temple was dedicated to Apollo Medicus at Rome, probably next to the temple of Bellona.
- Paean (/ PEE-ən; Παιάν, Paiān),physician, healer 
- Parnopius (/ NOH-pee-əs; Παρνόπιος, Parnopios), from πάρνοψ, "locust"
Founder and protector
- Agyieus (/ JY-i-yoos; Ἀγυιεύς, Aguīeus), from ἄγυια, "street", for his role in protecting roads and homes
- Alexicacus (/ KAY-kəs; Ἀλεξίκακος, Alexikakos), literally "warding off evil"
- Apotropaeus (/ PEE-əs; Ἀποτρόπαιος, Apotropaios), from ἀποτρέπειν, "to avert"
- Archegetes (/ KEJ-ə-teez; Ἀρχηγέτης, Arkhēgetēs), literally "founder"
- Averruncus (Roman) (/ RUNG-kəs; from Latin āverruncare), "to avert"
- Clarius (/ KLARR-ee-əs; Κλάριος, Klārios), from Doric κλάρος, "allotted lot"
- Epicurius (/ KEWR-ee-əs; Ἐπικούριος, Epikourios), from ἐπικουρέειν, "to aid"
- Genetor (/ JEN-i-tər; Γενέτωρ, Genetōr), literally "ancestor"
- Nomius (/ NOH-mee-əs; Νόμιος, Nomios), literally "pastoral"
- Nymphegetes (/ FEJ-i-teez; Νυμφηγέτης, Numphēgetēs), from Νύμφη, "Nymph", and ἡγέτης, "leader", for his role as a protector of shepherds and pastoral life
Prophecy and truth
- Coelispex (Roman) (/ SEL-i-speks), from Latin coelum, "sky", and specere "to look at"
- Iatromantis (/ MAN-tis; Ἰατρομάντις, Iātromantis,) from ἰατρός, "physician", and μάντις, "prophet", referring to his role as a god both of healing and of prophecy
- Leschenorius (/ NOR-ee-əs; Λεσχηνόριος, Leskhēnorios), from λεσχήνωρ, "converser"
- Loxias (/ LOK-see-əs; Λοξίας, Loxias), from λέγειν, "to say", historically associated with λοξός, "ambiguous"
- Manticus (/ MAN-ti-kəs; Μαντικός, Mantikos), literally "prophetic"
Music and arts
- Musagetes (/ SAJ-i-teez; Doric Μουσαγέτας, Mousāgetās), from Μούσα, "Muse", and ἡγέτης "leader"
- Musegetes (/ SEJ-i-teez; Μουσηγέτης, Mousēgetēs), as the preceding
- Aphetor (/ FEE-tər; Ἀφήτωρ, Aphētōr), from ἀφίημι, "to let loose"
- Aphetorus (/ FET-ər-əs; Ἀφητόρος, Aphētoros), as the preceding
- Arcitenens (Roman) (/ TISS-i-nənz), literally "bow-carrying"
- Argyrotoxus (/ TOK-səs; Ἀργυρότοξος, Argyrotoxos), literally "with silver bow"
- Hecaërgus (/ UR-gəs; Ἑκάεργος, Hekaergos), literally "far-shooting"
- Hecebolus (/ SEB-ə-ləs; Ἑκηβόλος, Hekēbolos), "far-shooting"
- Ismenius (/ MEE-nee-əs; Ἰσμηνιός, Ismēnios), literally "of Ismenus", after Ismenus, the son of Amphion and Niobe, whom he struck with an arrow
Celtic epithets and cult titles
Apollo was worshipped throughout the Roman Empire. In the traditionally Celtic lands he was most often seen as a healing and sun god. He was often equated with Celtic gods of similar character.
- Apollo Atepomarus ("the great horseman" or "possessing a great horse"). Apollo was worshipped at Mauvières (Indre). Horses were, in the Celtic world, closely linked to the sun.
- Apollo Belenus ('bright' or 'brilliant'). This epithet was given to Apollo in parts of Gaul, Northern Italy and Noricum (part of modern Austria). Apollo Belenus was a healing and sun god.
- Apollo Cunomaglus ('hound lord'). A title given to Apollo at a shrine at Nettleton Shrub, Wiltshire. May have been a god of healing. Cunomaglus himself may originally have been an independent healing god.
- Apollo Grannus. Grannus was a healing spring god, later equated with Apollo.
- Apollo Maponus. A god known from inscriptions in Britain. This may be a local fusion of Apollo and Maponus.
- Apollo Moritasgus ('masses of sea water'). An epithet for Apollo at Alesia, where he was worshipped as god of healing and, possibly, of physicians.
- Apollo Vindonnus ('clear light'). Apollo Vindonnus had a temple at Essarois, near Châtillon-sur-Seine in present-day Burgundy. He was a god of healing, especially of the eyes.
- Apollo Virotutis ('benefactor of mankind?'). Apollo Virotutis was worshipped, among other places, at Fins d'Annecy (Haute-Savoie) and at Jublains (Maine-et-Loire).