He has stopped taking boxing lessons and goes to the ballet class.

(In this sentence, what does 'class'mean? Does 'class' mean 'lesson'? Or does 'class' mean the 'class' as in ' He is a student of Class 1-1'?)

'Class' here means the gathering of students and teacher for a lesson.

In this sentence, the word "class" refers to a group or session of people taking ballet lessons together. In general, the term "class" can have different meanings depending on the context.

In the context of education or learning, "class" often refers to a group of students who are taught together by a teacher. For example, "He is a student of Class 1-1" signifies that the person is a member of a particular group of students in that specific grade level.

However, in the sentence you provided, "class" specifically refers to the ballet class, which is a particular session or group of people learning ballet. So, in this case, "class" means the same as "lesson" or a session of learning a specific activity, in this case, ballet.