Laundry detergent, or washing powder, is a substance that is a type of detergent

Detergent

A detergent is a surfactant or a mixture of surfactants with "cleaning properties in dilute solutions." In common usage, "detergent" refers to alkylbenzenesulfonates, a family of compounds that are similar to soap but are less affected by hard water...

 (cleaning agent) that is added for cleaning laundry

Laundry

Laundry is a noun that refers to the act of washing clothing and linens, the place where that washing is done, and/or that which needs to be, is being, or has been laundered...

. In common usage, "detergent" refers to mixtures of chemical compounds including alkylbenzenesulfonates, which are similar to soap but are less affected by "hard water

Hard water

Hard water is water that has high mineral content . Hard water has high concentrations of Ca2+ and Mg2+ ions. Hard water is generally not harmful to one's health but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling...

." In most household contexts, the term detergent refers to laundry detergent vs hand soap or other types of cleaning agents.