This article aims to discuss function words in surnames, such as vel, alias, de, in selected countries with European naming traditions, with particular reference to Poland. Despite the many centuries of surname evolution, such function words are still present in some contemporary surnames in Poland, and quite common in certain other regions (Spanish and Portuguese-speaking areas). In the article, surnames have been divided into two categories: the prepositional type (e.g. de, von, van, du, della), where the relationship between the conjoined name elements (usually the given name and the surname) is that of subordination, and the conjunctional type (e.g. y, e, sive, alias, vel) where the relationship between the conjoined elements (usually two surnames) is one of coordination, with the function word meaning „and” or „or”. From a grammatical perspective, however, not all function words are prepositions or conjunctions, as there are examples of closed or open compounds formed from prepositions and articles (French du, Dutch van der), as well as of participles (Latin dictus, German genannt). The paper addresses the various types of function words in surnames, outlining their genesis in some cases, as well as exploring issues that arise from their everyday use, especially in instances where two different naming cultures come into contact. Statistics on the frequency of Polish surnames (both past and present) containing function words are given. These data are also used to model the decline and eventual exctinction of function words in the Polish anthroponomasticon.