In Release It!, terms related to stability:

• transaction: is an abstract unit of work processed by the system
• mixed workload: is a combination of different transaction types processed by a system.
• system: the complete, interdependent set of hardware, applications, and services required to process transactions for users
• stability: resilient system keeps processing transactions, even when there are transient impulses, persistent stresses, or component failures disrupting normal processing
• stress (to the system): is a force applied to the system over an extended period.
• impulse: is a rapid shock to the system.
• a material changes shape when stress is applied. This change in shape is called the strain.
• The original trigger and the way the crack spreads to the rest of the system, together with the result of the damage, failure mode.
• crumple zones: areas designed to protect passengers by failing first. called crackstoppers

All of these are quotes from the book.