In this study, it was aimed to study the mathematical language skills that the 7th grade students use in defining the circle and its elements. In the study, the mathematical language skills of students that they use in defining the circle and its elements in a scenario were compared to the mathematical language skills they use in defining them when their names are given. The sampling of the study consists of 138 students of 7th grade. A scenario of 7 questions requiring the students to define the circle and its elements (center, radius, diameter, secant, chord, tangent) was arranged by the researchers and students were asked to respond these questions. Also, the students were asked to define the circle and its elements when their names were given. The students' mathematical language skills were examined in terms of their visual and verbal skills of definition. It was concluded that the students' mathematical language skills they used in defining the circle and its elements in a scenario were at a level that should be advanced, but their mathematical language skills they used in defining when their names were given is at a sufficient level. In addition, it was observed that the students had difficulty in defining the concept of tangent in a scenario at most and in defining the concept of chord when the names were given.