https://en.wikipedia.org/wiki/Responsibility_assignment_matrix

• R: Responsible — Those who complete the task. There is at least one role with a participation type of responsible, although others can be delegated to assist in the work required.
• A: Accountable (also approver or approving authority) — The one ultimately answerable for the correct completion of the deliverable or task, ensuring the prerequisites of the task are met, and delegating the work to those responsible. Accountable stakeholders sign off and approve work that responsible stakeholders provide. According to some theories of project management, there must be only one accountable stakeholder specified for each task or deliverable.
• C: Consulted — Those whose opinions are sought, such as subject-matter experts, and with whom there is two-way communication.
• I: Informed — Those who are kept up-to-date on progress, often only on completion of the task or deliverable, and with whom there is just one-way communication.