Keeping critical information and records available through disruption: outages, disasters, staff turnover. 'Vital records' are the subset needed to keep essential services running.
Recordkeeping and continuity are linked: the standard ties high risk/high value information to continuity strategies and plans. 'Vital records' are the subset an organisation needs to keep essential services running through a disruption, and they should sit in resilient systems.
IAR turns terms like this into working practice: assets classified against your disposal authority, stewarded by position, and ready to evidence.