The word anatomy comes from the Greek ana-meaning up or through + tome meaning a cutting. Anatomy was once a cutting up because the structure of the body was originally learned through dissecting it. The word histology came from the Greek histo- meaning tissue + logos, treatise.
Definition: Reliability is the degree to which a measurement instrument gives the same results each time that it is used, assuming that the underlying thing being measured does not change.
In reliability theory and reliability engineering, the term availability has the following meanings: 1  The degree to which a system, subsystem or equipment is in a specified operable and committable state at the start of a mission, when the mission is called for at an unknown, i.e. a random, time. Simply put, availability is the proportion of time a system is in a functioning condition.