1. As far as is related to, regards, or concerns someone; to the degree that someone is involved or a part of (something). For the employees' part, the merger means that many will be losing their jobs. Jane for her part has been instrumental in getting this project off the ground.

2. As comes from or is done by one. Guarantees for the banks' part must be provided to assure the country's citizens that their money is safe during this period of recovery. There has been no shortage of effort for his part to make sure this campaign has been successful.