Cetyl alcohol is a mild fatty alcohol used as an emollient (moisturizing ingredient), emulsifier, thickener and carrier for other ingredients. It can be extracted naturally, as in coconut oil alcohol, or manufactured synthetically. Both forms are considered safe and effective for the skin.
It is one of the longest known fatty alcohols, discovered in 1913 when a French chemist isolated it from whale oil (hence the name "cetyl", which is derived from Cetacea, the taxonomic infraorder in which whales are classified). https://www.paulaschoice.com/ingredient-dictionary/ingredient-cetyl-alcohol.html?q=cetyl%20alcohol&fdid=ingredients