Great elders of the Alter Rebbe's chassidim used to say that yechidus (private audience with the Rebbe) means: "clear," "designated," "united." The sources of these three interpretations are in Shekalim 6:2, Yevamot 62a, and Bereishit Raba 20.

This means that the idea of yechidus is:

To clarify one's own status;

To designate a mode of avoda for him in "turn(ing) away from evil" and in the acquisition of fine character traits;

And that he should bind himself1 in total oneness, and utterly dedicate himself1 with all his desires.