Description: characteristic of a structure to resist gradual degradation of its serviceability in a given environment for the design service life; Name: durability
Description: Ability of an item to perform a required function under given conditions of use and maintenance, until the end of useful life ; Name: Durability
Description: variable quantity, which is not influenced by the control but is introduced into the control system from outside with the aim of making the final controlled variable follow it in a given relationship; Name: command variable