Service Level Objective - specific measurable target for service performance. Like setting a goal to answer customer calls within 30 seconds, 95% of the time.
A web service sets an SLO of responding to API requests within 200 milliseconds for 99% of requests.
While major cloud providers do not have a specific service named SLO, they offer monitoring and management tools that help define and track SLOs. These tools allow users to set performance targets and measure service reliability.