Sa-fora

Is Sa-fora strictly a word for slave among the Wagon Peoples?

I can understand why Sa-fora could be thought to only pertain to the Wagon Peoples, since it is mentioned in Book 4, Nomads of Gor during the time Tarl goes to see the Wagon Peoples. This is a widely favorite book and the word "Sa-fora" is not mentioned again until Book 8, Hunters of Gor.

"Sa-fora" is found in the Gor Series four times. For context, I listed a little about the setting when the word is mentioned / described. I didn't find Sa-fora without a hyphen anywhere in the series. The only other word(s) I found meaning anything close to a female slave is "La Kajira".

First mentioned in Nomads of Gor, while Tarl visits the Wagon Peoples and met Kamchak. The sentence after this section describes how a slave clad Kajir would be appear.

Kajira is perhaps the most common expression for a female slave. Another frequently heard expression is Sa-Fora, a compound word, meaning, rather literally, Chain Daughter, or Daughter of the Chain.
Nomads of Gor     Book 4     Page 29

The second time is in Hunters of Gor. Tarl leaves Ilene gagged and later returns to the camp of Marlenus. Marlenus of Ar had been staked out in a conquest circle.

The brazier, fierce with heat, stood not two yards from Marlenus of Ar. Its coals were poked and stirred with one of the metal bars. Then one of the men of Tyros lifted the iron, glowing redly, from the fire. Its marking surface, its termination, soft and red in the night, was in the form of a large, block letter in Gorean script, the initial of Kajirus, a common Gorean expression for a male slave. A female's brand is smaller, and much more graceful, usually being the initial, in cursive script, of Kajira, the most common Gorean expression for a slave female. Some cities, Treve, for example, have their own brands. The Wagon Peoples, too, each have an individual brand for their female slaves. The Tuchuk brand, tiny and fine, is the paired bosk horns. Tana, the paga slave in Lydius, wore it. The brand of the Kataii is that of a bow, facing to the left; the brand of the Kassars is that of the three-weighted bola; the brand of the Paravaci is a symbolic representation of a bosk head, a semicircle resting on an inverted isosceles triangle. Another common expression for a female slave, incidentally, the initial of which, in cursive script, is sometimes used to mark a girl, is Sa-Fora, which means, rather literally, Chain Daughter.
Hunters of Gor     Book 8     Page 194

The third and fourth times are really close together in Witness of Gor. A barbarian, Janice, describes her fulfillment, happiness and joy! I truly like this passage because of her love and happiness for her slavery, so I included more of these quote. The Wagon Peoples are only mentioned in Witness in regards to their dung sack punishment.

But I suppose, by now, it is evident to all that I am a kajira, or sa-fora. But of course it is not evident! How could it be? Forgive me. You do not know these words. Aside from the words, of course, my condition, my status, is doubtless clear to you. Would it not be clear from the speaking of chains, and collars, and such? You may find it objectionable. I do not. I love it. In it I find my fulfillment, my happiness, my joy! Perhaps you think what I am is degrading, and perhaps it is, but, if so, it is a delicious, precious, joyful degradation which I treasure, and in which I thrive and prosper, and one I would not, at the expense of my very life, have otherwise.

It is a thing of softness, heat, devotion, obedience, service, beauty and love.

In it I am happy, and fulfilled, completely, perfectly, totally as a total woman, as I could be in no other way.

In brief, the word sa-fora means "Chain Daughter" or "Daughter of the Chain". The word kajira, on the other hand, is by far the most common expression in Gorean for what I am, which is, as you have doubtless surmised, a female slave. Yes, slave. The male form is Kajirus. The plural of the first word is kajirae, and of the second kajiri. As kajira is the most common expression in Gorean for slave who is female, I suppose I might, in English be most simply, and most accurately translated, as "slave girl." In a collar, you see, understandably, all women are "girls." Almost all slaves on Gor are female. There are, of course, male slaves, but most are laborers, working in the fields, in quarries, in mines, on roads, and such, in chains and under whips. Some women keep male silk slaves, but they are rare. The Gorean view is that slavery is appropriate for the female, and not for the male. A saying, a saying of men, of course, has it that all women are slaves, only that some are not yet in the collar. I know now, of course, as I did not earlier, that there are many free women on Gor, and, indeed, that most women on Gor are free. An exception seems to be a city called Tharna. I do not know why that is the case.
Witness of Gor     Book 26     Pages 101-102