Both dominant and auxiliary (lead and supporting) share the designation of "preferred", and by themselves determine the one-in-sixteen type.
The tertiary and inferior develop later, and the tertiary is known as "the eternal child" or "relief", while the inferior remains immature even longer. The way we behave with it is also described as "childish" and immature. So we see a common thread with both postions of functions: immaturity.
Likewise, the fifth and sixth (in the nearest area of the shadow) are "opposing personality" and "immobilizing" or "critical". The common theme here is resistance to something, either present or future.
The deepest shadow consist of "deceiving" and "destructive". Both share in common a regretting of actions taken with the function.
So I would name the four resultant pairs:
This is useful for grouping together the functions shared in common by either the two-letter function attitude combinations (SP, SJ, NP, NJ, TP, TJ, FP, FJ) or three letter "intelligence types": STP, STJ, NTP, NTJ, SFP, SFJ, NFP, NFJ), for whom either one or both functions wil fall into the same pair. Keirsey had said that I/E was the least important factor, and a statistical study supported it. So when speaking of TP's, for instance, we can mention "resistant Te", or "regrettable Se". When talking about NTP's, they will both have "immature Si".