What term is used for the study of a theoretical or skill operation in cosmetology?

The term that refers to the study of a theoretical or skill operation in cosmetology is 'subject.' In an educational context, a 'subject' encompasses the broad area of study that focuses on specific knowledge or skills pertinent to a particular field, such as cosmetology. This includes various disciplines and techniques that students must learn to become proficient in their profession.

While the other options—class, training, and coursework—are related to the educational process, they have distinct meanings. A 'class' typically denotes a specific instance of instruction within a broader subject area. 'Training' generally refers to practical skill development rather than theoretical study, and 'coursework' usually implies the assignments and tasks assigned as part of completing a course within a subject. Thus, 'subject' captures the essence of the theoretical study involved in learning cosmetology operations comprehensively.