Service Level Agreement - a commitment between service provider and customer defining expected performance and reliability. Like a warranty that promises your service will work 99.9% of the time or you get compensation.
Cloud providers offer SLAs guaranteeing 99.99% uptime, meaning your application should only be down for about 4 minutes per month maximum.
An SLA (Service Level Agreement) is a contractual commitment, not a single cloud service. AWS, Azure, Google Cloud, and OCI each publish SLAs for many individual services (for example, compute, storage, databases) that define availability targets, how uptime is measured, exclusions, and service credit remedies.