1
general::
Also, on one's part;on the part of one. 1. So far as one is concerned, as regards one's share in the matter. For example, You may want to go out, but for my part I want to stay home, or On the part of the others, they expect a small share of the profits. [Mid-1400s] 2. Regarding or with respect to the one specified, as in For the Confederates' part, a daring strategy accounted for their victory at Chancellorsville, or, as Thomas Macaulay put it in History of England (1849): "No excess of tyranny on the part of a prince can justify active resistance on the part of a subject." [c. 1400]
American Heritage Idioms