dictionary [dictionaries](publication that explains the meanings of an ordered list of words) noun [UK: ˈdɪk.ʃən.ri] [US: ˈdɪk.ʃə.ˌne.ri]May I borrow your dictionary? = Posso prendere in prestito il tuo vocabolario?
lexicon [lexicons](vocabulary used by an individual) noun [UK: ˈlek.sɪkən] [US: ˈlek.sɪˌk.ɑːn]
vocabulary [vocabularies](list of words) noun [UK: vəˈk.æ.bjʊ.lə.ri] [US: voˈkæ.bjə.ˌle.ri]What's that vocabulary? = Cos'è quel vocabolario?