"Mean time between outages" is commonly abbreviated as MTBO and is a key metric used in measuring the reliability of a system. It is defined as the average time elapsed between two consecutive failures of a system. To avoid repetitiveness in technical reports or conversations, synonyms for MTBO can be used. Such synonyms include "mean time to repair," "mean time to failure," "mean time between failures" (MTBF), and "system uptime." Each term may have a slightly different meaning, but they are all related to the reliability of the system and can be used interchangeably in most cases.