development of word definition skill in persian-speaking 54-90-month-olds

Objectives: word definition skill is a complex language ability in which metalinguistic awareness and literacy skills play a critical role. the present study examined the development of word definition skills in persianspeaking children aged 4.5 to 7.5 years, concerning content and form aspects.methods: this was a crosssectional and analyticdescriptive study. the study subjects were 107 children of three age groups, as follows: 5465montholds, 6677montholds, and 7890montholds. the study participants were selected from kindergartens and schools in districts 1, 7, and 17 of tehran city, iran, by multistage sampling method. in the word definition task, children were requested to define the words. to analyze the obtained data, the kruskalwallis test was used.results: the obtained results indicated that the mean score of content (p=0.001) and form (p=0.002) aspects of word definition significantly increased with age in the study participants.discussion: a shift from functional and objective responses towards metalinguistic definitions, i.e. further developed in terms of content and form, was observed with aging. at the age of 7 years, definitions reflect the hierarchical nature of nouns, and applying the class name begins at this age. the age of reaching a specific class seems to be affected by the lexical category.