Objectives and key results (OKR) is a goal-setting framework used by teams (or individuals) to define and track their goals and outcomes.
Usually, and OKR contains concrete, clearly defined goals (Objectives) and 4-5 measurable outcomes to track the objective (key results). While objectives are clearly defined, it has to be inspirational for the team. KRs should be measurable and method of Measurement should also have clarity. KRs can be difficult, but not impossible.
Source
BOOK- Radical Focus —Defining Key Results, 1:1 with @BruceMcCarthy