Ma'anar ƙamus na "ɗauri mai ƙarfi" shine ma'aunin juriyar ruwa don gudana, wanda aka ayyana a matsayin rabon danniya na shearing zuwa saurin saurin cikin ruwa. A mafi sauƙi, ma'auni ne na kauri ko mannewa na ruwa wanda ke ƙayyade yawan ƙarfin da ake buƙata don sa shi gudana a wani ƙayyadadden ƙimar. Danko mai ƙarfi ana bayyana shi da alamar "μ" kuma ana bayyana shi a cikin raka'a na Pa·s (pascal-seconds) ko N·s/m² (sabbin daƙiƙai a kowace murabba'in mita).