Everyone possesses a diverse range of vocabulary. When it comes to the children, vocabulary is most often enriched in schools during the teaching process. The acquisition of the meaning of new words in schools is still not adequately represented, and in some, this problem is even being neglected. Expanding a child’s vocabulary depends on numerous things, but the key role is played by the primary school teacher who needs to enrich the lesson with strategies for understanding the meaning of words. Therefore, the topic Strategy for understanding the meaning of words in the classroom context was chosen for the thesis. The aim of the research, which is analysed in the practical part of the paper, is to determine which strategies for understanding the meaning of words primary teachers use most often. There are two possible strategies, the so-called unplanned teaching ( refers to spontaneous reactions of teachers to assist when students reading a text come across a word whose meaning is unknown) or the so-called planned teaching ( focused on the intentional, explicit application of selected teaching strategies) to expand the student's vocabulary. A questionnaire was used for the research and it was conducted on a sample of 81 primary school teachers in the areas of Osijek-Baranja County, Požega-Slavonia County, Virovitica-Podravina County, Primorje-Gorski Kotar County, Split-Dalmatia County and the City of Zagreb.