The three key mechanisms in deriving the secondary meaning of polysemous lexemes are lexical metaphor, lexical metonymy and lexical synecdoche. Considering that lexical synecdoche has not received much attention so far, this paper will explore its role in creating the polysemous structure of Croatian lexemes. In this paper, lexical synecdoche is viewed as a predictable mechanism with several reversible transfers in its core: part for whole and whole for part, general for individual and individual for general, singular for plural and plural for singular, species for genus and genus for species. The formulas of these transfers are at the same time notations for conceptual metonymies which we consider the starting point for the creativity of lexical synecdoches. We do so because the metonymy and the synecdoche operate within a single conceptual domain, where one entity stands for another on the basis of their spatial, temporal, functional or causal relation. This common relation is why the synecdoche is usually considered a subcategory of metonymy. On the other hand, the metonymy and the synecdoche can be seen as separate lexical mechanisms because they are motivated by different types of relations between entities involved in the transfer. While the metonymic transfer is based on the closeness of entities in conceptual proximity as parts of the same domain, the transfer in synecdoche occurs between the domain itself and its integral part and turns from proximity to inclusion.Tri mehanizma ključna za izvođenje sekundarnih značenja polisemnih leksema jesu leksička
metafora, leksička metonimija i leksička sinegdoha. Budući da je leksička sinegdoha zasad dobila najmanje istraživačke pozornosti, u ovom ćemo radu ukazati na njezinu ulogu u oblikovanju polisemne strukture hrvatskih leksema. Leksičku ćemo sinegdohu opisati kao predvidljiv jezični mehanizam čije se funkcioniranje načelno može svesti na nekoliko reverzibilnih transfera: dio za cjelinu i cjelina za dio, opće za pojedinačno i pojedinačno za opće, singular za plural i plural za singular, jedinka
za vrstu i vrsta za jedinku. Formule navedenih transfera ujedno su zapisi pojmovnih metonimija koje smatramo kognitivnim ishodištem sinegdoške leksičke kreativnosti. Činimo to zato što i metonimija i sinegdoha operiraju unutar jedne pojmovne domene gdje jedan entitet zastupa drugi entitet na temelju prostorne, vremenske, funkcionalne ili uzročno–posljedične povezanosti. To im je zajedničko i zbog toga se sinegdoha obično drži podvrstom metonimije. S druge strane metonimija i sinegdoha imaju status zasebnih leksičkih mehanizama jer ih motiviraju različite vrste odnosa između entiteta zahvaćenih transferom. Dok metonimijski transferi proizlaze iz bliskosti entiteta koji obitavaju u pojmovnom susjedstvu kao dijelovi iste domene, sinegdoški se transferi odvijaju između same domene i njezina sastavnog dijela te nadrastaju bliskost i prelaze u inkluziju
