Answer:
I'm a cosmetologist, so I have a very good understand of what cosmetology is.
Cosmetology is a career. Cosmetologists are people who practice (or are licensed in) cosmetology.
Cosmetologists do many things. The most popular & widely known thing that cosmetologists do is hair. Styling, cutting, coloring, perming, fitting wigs, scalp treatments, and hair treatments are all part of cosmetology.
As well as hair, cosmetologists can apply false nails or acrylics. Also, manicures, pedicures, and polish changes are part of the nail aspect in cosmetology.
As far as skin care, cosmetologists are legally allowed to apply their knowledge shoulder up and knee down. Waxing, facials, and massages are all included in the skincare aspect of cosmetology. To legally wax below the shoulder and above the knee you need to have an Esthetician's license. Estheticians specialize in skin care.
Cosmetologists are licensed to do many different things, but I hope my answer gives you a good understanding of what we're able to do and what the job includes.