what is soap chemically known as?

Chemically , soap is a salt of a fatty acid ofter the sodium salt.

Soaps are obtained by treating vegetable or animal oils and fats with a strongly alkaline solution.

Fats and oils are composed of triglycerides: three molecules of fatty acids attached to a single molecule of glycerol.

The alkaline solution, often called lye, brings about a chemical reaction known as saponification. In saponification, the fats are first hydrolyzed into free fatty acids, which then combine with the alkali to form crude soap.

Glycerol, often called glycerin, is liberated and is either left in or washed out and recovered as a useful by-product according to the process employed.

sodium stearate is a typical soap.

A sodium, potassium or ammonium salt of a long-chain (plant or animal derived) fatty acid.