GREEK SURNAMES ARE MOST COMMONLY PATRONYMICS

Greek surnames are most commonly patronymics. Occupation, characteristic or ethnic background and location/origin-based surnames names also occur; they are sometimes supplemented by nicknames.
Commonly, Greek male surnames end in -s, which is the common ending for Greek masculine proper nouns in the nominative case. Exceptionally, some end in -ou, indicating the genitive case of this proper noun for patronymic reasons.
Although surnames are static today, dynamic and changing patronym usage survives in middle names in Greece where the genitive of father's first name is commonly the middle name.
Because of their codification in the Modern Greek state, surnames have Katharevousa forms even though Katharevousa is no longer the official standard.
Thus, the Ancient Greek name Eleutherios forms the Modern Greek proper name Lefteris, and former vernacular practice (prefixing the surname to the proper name) was to call John Eleutherios as Leftero-giannis.
Modern practice is to call the same person Giannis Eleftheriou: the proper name is vernacular (and not Ioannis), but the surname is an archaic genitive.
Female surnames, are most often in the Katharevousa genitive case of a male name. This is an innovation of the Modern Greek state; Byzantine practice was to form a feminine counterpart of the male surname (e.g. masculine Palaiologos, Byzantine feminine Palaiologina, Modern feminine Palaiologou).
In the past, women would change their surname when married, to that of their husband (again in genitive case) signifying the transfer of "dependence" from the father to the husband. In earlier Modern Greek society, women were named with -aina as a feminine suffix on the husband's first name: "Giorgaina", "Mrs George", "Wife of George". Nowadays, a woman's surname does not change upon marriage, though she can use the husband's surname socially. Children usually receive the paternal surname, though in rare cases, if the bride and groom have agreed before the marriage, the children can receive the maternal surname.
Some surnames are prefixed with Papa-, indicating ancestry from a priest, i.e. ."Papadopoulos", the "son of the priest (papas)". Others, like Archi- and Mastro- signify "boss" and "tradesman" respectively.
Prefixes such as Konto-, Makro-, and Chondro-, describe body characteristics, such as "short", "tall/long" and "fat". "Gero-" and "Palaio-" signify "old" or "wise".
Other prefixes include Hadji- which was an honorific deriving from the Arabic Hadj or pilgrimage, and indicate that the person had made a pilgrimage (in the case of Christians to Jerusalem) and Kara- which is attributed to the Turkish word for "black" deriving from the Ottoman Empire era.
Arvanitic surnames are also common. For example, the Arvanitic word for "brave" or "pallikari" (in Greek) being "çanavar" or its shortened form "çavar" was pronounced "tzanavar" or "tzavar" giving birth to traditional Arvanitic family names like "Tzanavaras" and/or "Tzavaras".[12]
Most Greek patronymic suffixes are diminutives, which vary by region. The most common Hellenic patronymic suffixes are:
-poulos/-poulou, which has Latin origin (pullus) and means "the little", representing "the son of ...", so a man whose family name is "Christopoulos" means that his father was named "Christos". This suffix is very spread mostly throughout the whole Greece and is original from the Peloponessus in particular.
-idis/-idou and -iadis/-iadou are both very ancient last names and clan forms used in the Pontus and Asia Minor regions, i.e. "Michailidis", the "clan of Michael"
-akis/-aki is associated primarily with Crete and the Aegean Islands. A patronymic signifying "little" and/or "son" therefore "Theodorakis" being "little Theodore".
Others, less common are:
-atos/-atou (From Cephallonia and other Ionian Islands under strong Italian influence);
-as/-a (From Macedonia and Epirus);
-ellis/-elli (From Lesvos Island);
-akos/-akou (From Mani in the Laconia region) and -eas/-ea (From Mani in the Messinia region);
-oglou (both genders, a Turkish root ending seen in immigrants from Asia Minor meaning "son of", i.e. Sarafoglou, "the son of Sarafis");
-ou (Genitive, from Cyprus).
The suffix -idis(often transliterated -ides in English and French languages) is the oldest in use. Zeus, for example was also referred to as Cronides ("son of Cronus").

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