And while we are considering terms that people assign different meanings to, and then forget that others are using other meanings for the same term, which causes a great deal of arguments, let's look at the term: Secret Chief.
In Golden Dawn, there is a lot of smoke and mirrors surrounding this term. Whether or not, an Order has made contact with the Secret Chiefs, or even believes in their existence, is the source of much of the opinion in the Golden Dawn community about whether or not a particular branch, or leader, is legitimate or not.
There are those who use the term Secret Chief to talk about entities that exist on the astral plane, who have evolved past the point of needing bodies, or perhaps never having a physical form in the first place; these entities are said to guide and inspire the Orders from a higher plane. Exactly when an entity becomes a Secret Chief and not just a random entity (angel, saint, demon, god, muse, old dead guy) is unclear. Aleister Crowley is the most notorious individual who claimed such contact, but he is definitely not even close to being the only one to make such a claim.
Others use the term to describe members of the ultimate esoteric secret society, so secret that even those they contact are not allowed to know their real identities. They are Uber-Adepts, of at least the 8=3 Magister Templi Grade, and more often than not are members of another esoteric tradition. They tend to be from regions that birth new esoteric traditions and movements.
A big point of concern among those who care about such things is whether or not these Secret Chiefs have actually crossed the Abyss or not. Some say that only those who have crossed the Abyss can be Secret Chiefs. Others say that it is not crossing the Abyss that counts, but the production and use of the elixir of life.
These are the two most common definitions of Secret Chief.
(There is another definition that rests solely on function, but you are unlikely to run into anyone that seriously gives it the time of day.)
The problem with both of these definitions, and their variations, is that the access to the Secret Chiefs is so terribly restricted that only a single person in any particular generation, or time period, can be in contact with them. And when more than one person, or Order, claims to have access to them, one has to presume that someone is lying, or perhaps delusional.
(There is also the slight matter of higher fraud: how can you be sure that your "Secret Chief" is not lying about being a Secret Chief?)
In the end, the only advice I can give is to beware of the disagreement in how people are using the term, and judge leaders and Orders solely on their usefulness to you personally.
~~~To Be Continued~~~