1.2.12+Define+the+term+usability

Usability is defined by **5 quality components**: >
 * **Learnability**: How easy is it for users to accomplish basic tasks the first time they encounter the design?
 * **Efficiency**: Once users have learned the design, how quickly can they perform tasks?
 * **Memorability**: When users return to the design after a period of not using it, how easily can they reestablish proficiency?
 * **Errors**: How many errors do users make, how severe are these errors, and how easily can they recover from the errors?
 * **Satisfaction**: How pleasant is it to use the design? - []