Scientific plant names are a valuable lexical layer for studying categorisation as a process of verbalised ordering of knowledge of the environment, specific to each variant of the scientific and language picture of the world. The aim of the paper was to analyse the factors determining the semantic motivation of scientific names of weeds in Latin and Ukrainian. The study used etymological and semantic analysis of phytonyms, comparative method and generaliation. The research material was 100 binomial plant names, obtained as a result of continuous sampling from the guide of weeds in Ukraine. The paper investigated productive patterns of plant scientific names’ formation in the Latin and Ukrainian languages, examined the main motives for plant naming in both languages. This study showed that the scientific plant names of in both languages are motivated by a combination of several common aspects including appearance, properties, place of occurrence, use and other fixed in the generic name and specific epithet. The findings confirmed the conclusions of modern research that the mechanism of nomination is based on the semantic motivation of phytonyms, determined by the choice of the motivator from the zone of information predominantly about the appearance (shape, colour, size, similarity of plants or their parts) and properties (taste, smell, tactile sensation, positive and negative properties). The results can be used in the training of specialists in the field of knowledge “Agrarian Sciences and Food”
O. Yu. Balalaieva (Sat,) studied this question.