[common] Opposite of ‘test’. Refers to actual real-world data or a program working with it. For example, the response to “I think the record deleter is finished” might be “Is it live yet?” or “Have you tried it out on live data?” This usage usually carries the connotation that live data is more fragile and must not be corrupted, or bad things will happen. So a more appropriate response might be: “Well, make sure it works perfectly before we throw live data at it.” The implication here is that record deletion is something pretty significant, and a haywire record-deleter running amok live would probably cause great harm.