Maryam Malekian - Department of Speech Therapy, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
Talieh Zarifian - Department of Speech Therapy, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
Robab Teymouri - Pediatric Neurorehabilitation Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.

Objectives: Word definition skill is a complex language ability in which meta-linguistic awareness and literacy skills play a critical role. The present study examined the development of word definition skills in Persian-speaking children aged ۴.۵ to ۷.۵ years, concerning content and form aspects. Methods: This was a cross-sectional and analytic-descriptive study. The study subjects were ۱۰۷ children of three age groups, as follows: ۵۴-۶۵-month-olds, ۶۶-۷۷-month-olds, and ۷۸-۹۰-month-olds. The study participants were selected from kindergartens and schools in districts ۱, ۷, and ۱۷ of Tehran City, Iran, by multi-stage sampling method. In the word definition task, children were requested to define the words. To analyze the obtained data, the Kruskal-Wallis test was used. Results: The obtained results indicated that the mean score of content (P=۰.۰۰۱) and form (P=۰.۰۰۲) aspects of word definition significantly increased with age in the study participants. Discussion: A shift from functional and objective responses towards meta-linguistic definitions, i.e. further developed in terms of content and form, was observed with aging. At the age of ۷ 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.

Development, Word definition, Child, Semantic