"ILM is comprised of the policies, processes, practices, and tools used to align the business value of information with the most appropriate and cost-effective IT infrastructure from the time information is conceived through its final disposition" (SNIA, via Infoworld).
"All information, or data, in a storage network has a specific lifecycle, from the time the information enters an organization's system to the time it is archived or removed from the system. ... The management of the information lifecycle involves keeping the data accessible to the users who need the information and determining how the information is stored based on how high of a priority the information has in the organization at any given moment" (Webopedia). Information lifecycle management is "a standards-based approach to automating datacenter operations based on business requirements and business processes" (Mike Peterson, via Infoworld).
"ILM products automate data management by organizing data and automating data migration into tiers categorized by policy criteria. ... Policy [is] determined by business goals and drivers. Storage and information policies are shaped by executive and managerial determinations of IT governance and management, service level agreements (SLA), change control processes, and system availability and recovery time requirements in the event of unexpected events, such as accidents or disasters" (Techopedia).
A definitive guide to data definitions and trends, from the team at Stitch.