Gospodar or hospodar, also gospodin as a diminutive, is a term of Slavic origin, meaning "lord" or "master". The compound (Belarusian: гаспадар, Bulgarian: господар, Macedonian: господар, Serbo-Croatian: gospodar, господар, Ukrainian: господар) is a derivative of gospod / gospodin, transl. (L)ord / gentleman or Sir, or when spelled with a capital G (Gospod / Gospodin) it translates as Lord for God.

The etymology of the word can be traced back to the connotation of the Indo-European patron-client and guest-host relationship.

Rich patrons sponsored feasts as a way for them to promote and secure a political hierarchy built on the unequal mobilization of labor and resources, by displaying their generosity towards the rest of the community. Rivals competed publicly through the size and complexity of their feasts, and alliances were confirmed by gift-giving and promises made during those public gatherings. The host of the feast was called the *ghosti-potis, the 'lord of the guests', who honored the immortal gods and his mortal guests with gifts of food, drink, and poetry.

In Proto-Indo-European, the term *ghós-ti-, whose original meaning must have been "table companion", could either mean a host or a guest. The connotation of an obligatory reciprocity between both guests and hosts has persisted in descendant cognates, such as Latin hospēs ("foreigner, guest; host"), Old English ġiest ("stranger, guest"), or Old Church Slavonic gostĭ ("guest") and gospodĭ ("master").

The *potis compound is rare as a Slavic lexeme. It might have arisen as an additional calque of the Greek 'despótēs' (-πότης), yet the presence of *potis in Iranic languages e.g Avestani dəng paitiš “master of the house”, might indicate an older and universal usage of the compound. The word *batь (attested in Bulgarian and Ukrainian and meaning bigger brother and later additionally transforming into 'bashta' or father in Bulgarian) is shared among Uralic, Turkic and Iranic languages, with the p- > b- transformation likely indicating a transition through a Turkic language of an originally Indo-European word. Another view is that it is a baby-talk modification of *bratrъ (“brother”), since it morphologically resembles kin terms ending in *-tь, including *zętь (“son-in-law”), *tьstь (“father-in-law”), *netь(jь) (“nephew”). The Proto-Slavic word *pǫdurъ (“watchman, guard”) is also notable in its relation to the word and is a later loanword in Hungarian.

The pronunciation "hospodar" (i.e. with a fricative) of a word written as "господар" in some Slavic languages, which retains the Cyrillic script, could be due to the influence of either Ukrainian, where the first letter is pronounced as [ɦ], or that of Belarusian and Church Slavonic, where it is pronounced as [ɣ].

In the Slavic language family, compound "gospodar" / "hospodar" is usually applied to the master/owner of a house/household or other property and also the head of a family or clan. In some languages the hospodars house or household is called "hospóda", however, in other, such as in South Slavic, "(g)ospoda" translates as "gentry" as just a plural derived from "gospodin" and/or "gospodar". There is also an alternative form for the head of the household, "gazda", "gazdarica" as a feminine, and "gazdinstvo" as a household and/or property. "Gazda" form is also common in Hungary.

In Slovene, Macedonian, Serbo-Croatian and Bulgarian, "gospodar" (господар) means a "master", "lord", or "sovereign lord". Other derivatives of the word include "gospodarstvo", which means ownership, household and property, and economy, gospodin (господин), which translates as "Sir", "gentleman" and/or "Mister" (in Bulgarian, Russian, Macedonian, and Serbo-Croatian), and "gospodstvo" (in Serbo-Croatian). Meanwhile, "Gospod" and "Gospodin" refers to God and is identical to Russian gospod` (господь, "the Lord") and gosudar' ("sovereign").