Main Difference
The main difference between Soap and Detergent is that the Soap is a sodium salt of fatty acids ( long chain carboxylic acids ), used for washing and cleaning and Detergent is a purifying or cleansing agents, usually salts of long-chain aliphatic bases or acids, that exert cleansing (oil-dissolving) and antimicrobial effects through a surface action that depends on possessing both hydrophilic and hydrophobic properties
Soap
Soap is a salt of a fatty acid used in a variety of cleansing and lubricating products. Household uses for soaps include washing, bathing, and other types of housekeeping, where soaps act as surfactants, emulsifying oils to enable them to be carried away by water. In industry, they are used as thickeners, components of some lubricants, and precursors to catalysts.
Detergent
A detergent is a surfactant or a mixture of surfactants with cleaning properties in dilute solutions. These substances are usually alkylbenzenesulfonates, a family of compounds that are similar to soap but are more soluble in hard water, because the polar sulfonate (of detergents) is less likely than the polar carboxylate (of soap) to bind to calcium and other ions found in hard water.
In most household contexts, the term detergent by itself refers specifically to laundry detergent or dish detergent, as opposed to hand soap or other types of cleaning agents. Detergents are commonly available as powders or concentrated solutions. Detergents, like soaps, work because they are amphiphilic: partly hydrophilic (polar) and partly hydrophobic (non-polar). Their dual nature facilitates the mixture of hydrophobic compounds (like oil and grease) with water. Because air is not hydrophilic, detergents are also foaming agents to varying degrees.
Soap (noun)
a substance able to mix with both oil and water, used for cleaning, often in the form of a solid bar or in liquid form, derived from fats or made synthetically
“I tried washing my hands with soap, but the stain wouldn’t go away.”
Soap (noun)
a metallic salt derived from a fatty acid
Soap (noun)
a flattery or excessively complacent conversation
Soap (noun)
, specially when used for bribing purposes
Soap (noun)
A soap opera.
Soap (verb)
To apply soap to in washing.
“Be sure to soap yourself well before rinsing.”
Soap (verb)
To cover, lather or in any other form treat with soap, often as a prank.
“Those kids soaped my windows!”
Soap (verb)
To be discreet about (a topic).
Soap (verb)
To flatter; to wheedle.
Detergent (noun)
Any non-soap cleaning agent, especially a synthetic surfactant.
Detergent (adjective)
Having the power to clean.
Detergent (noun)
a water-soluble cleansing agent which combines with impurities and dirt to make them more soluble, and differs from soap in not forming a scum with the salts in hard water
“packets of detergent”
“liquid detergents”
Detergent (noun)
any additive with a similar action to a detergent, e.g. an oil-soluble substance which holds dirt in suspension in lubricating oil.
Detergent (adjective)
relating to detergents or their action
“staining that resists detergent action”