There are various synonyms for the word "hard soap" that can be used in lieu of this term. These options include bar soap, solid soap, cake soap, soap block, and soap slab. Bar soap is a widely recognized term, often used to refer to hard soap, and is commonly found in households and businesses alike. Solid soap and cake soap both refer to the compact, hardened form that soap can take on, while soap block and soap slab tend to be used more frequently in industrial and manufacturing contexts. Regardless of the specific synonym chosen, all refer to the same type of solid, typically rectangular soap that is firm to the touch.