What is the difference between "a good deed" (hasanah) and "a righteous act" (amal salih)?

A good deed (hasana) is anything that pleases a person in their soul, body, and circumstances. It may refer to a righteous act, as in the Almighty’s saying: "And whoever earns a good deed - We will increase for him therein good." And it may refer to the reward for a righteous act, which is its most common usage, an example of which is the Almighty’s saying: "Indeed, Allah does not wrong [even] as much as a [weight of] atom; and if there is a good deed, He multiplies it and gives from Himself a great reward," and the Prophet’s (peace be upon him) saying: "Whoever recites a letter from the Book of Allah, he will have a good deed thereby, and a good deed is multiplied tenfold."