Talieh Zarifian - University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
Shima Matloubi - University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
Tahereh sima Shirazi - University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
Enayatollah Bakhshi - University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.

Objectives: Word definitional skills (WDSs) were classified according to the quality of both semantic content and syntactic form. The aim of the present study was to investigate the syntactic development in WDSs in typically developing school- age children. Methods: In this cross-sectional and descriptive-analytical study,  ۱۵۰ of typically developing school-age children participated by the  multistage sampling method in the second to sixth grade from primary schools in ۱, ۷ and ۱۷ municipal  districts of Tehran. The definition skill was assessed with word definition task. The reliability was assessed by two independent values and the validity was determined by the content. The results were  analyzed by the SPSS (۲۲th version)  statistical software and with the method of independent- samples T test, univariate analysis of variance and Tukey test. Results: The form analysis revealed that all children use phrase/clause  or simple sentence, transitional form and Aristotelian form frequently, but by increasing the age, definitions were developed from simple syntactic structure into Aristotelian form, in fact mean score of the form in word definition was significantly increased by age (P<۰.۰۰۱). Discussion: Owing to the findings of this study, the development of word definitional skills in terms of form was developed from phrase/clause or simple sentence and transitional form responses into Aristotelian form. Also WDSs are closely related to academic success and the development of literacy.

Definition, Development, Student, Syntax, Form