Etymologizing mdor bsdu ba or mdor ’du ba
It is quite a while since I have been speculating and etymologizing stuffs here. Several factors are responsible for this pause such as time, place, mood, and insight. Thinking of Rong-zom-pa’s (Theg tshul, p. 482) use of the expression mdo rnam pa gnyis su ’dus te provokes me to speculate a little about the etymology of mdor bsdu ba (“to summarize”) or mdor ’du ba (“to sum up to” or “to amount to” or “to be subsumable under”). As always, I consider bsdu ba a “heteronomous verb” and ’du ba an “autonomous verb.” Please do not suggest “voluntary” and “involuntary” instead because it is futile. The distinction between the two is not just a matter of being “transitive” and “intransitive.” Of course we can surmise (by the way “surmise” is not a British spelling of the American “surmize” which does not exist) that Tibetans knew and used the word mdo even before they knew of any Sūtric scriptures. So mdo is certainly to be seen as a purely Tibetan word and means a “string.” But what could be “primary” meaning of mdo? I propose two possible candidates, namely, “string” and “point of convergence.” The former does not seem to be recorded by Jäschke whereas the latter somehow is. Its meaning “axiom” or “aphorism” (and by extension also synoptic discourses of the Buddha) will be considered secondary. Of the two candidates, I feel that “string” is the primary meaning of mdo (just like Sanskrit sūtra) although I cannot rule out the other. A “string” or “cord” holds things together; it gathers and collects; to binds and joins things together. This meaning is most clear in the case of words such as mdo ’dzin (lit. “string-holder,” i.e. a director). So it would seem that a “point of convergence” or “meeting point” is made possible by “stringing” or “connecting” (roads, rivers, and valleys). Thus we can speak of lam mdo “cross-road” and chu mdo “confluence.” Also the “lower part of the valley” that merges with the plains and hence synonymous with mda’ and antonymous with phu “ridge” contains the meaning of “point of convergence.” It is in the latter sense that we can explain names of places such as Cha-mdo, A-mdo, Dar-rtse-mdo, and so on. But what does mdor bsdu ba or mdor ’du ba etymologically mean? I think mdor bsdu ba simply means “to gather [something] in a string” (and thus “to summarize”) or mdor ’du ba “to be subsumable in a string.” Hence Rong-zom-pa’s “X mdo rnam pa gnyis su ’dus” can literally mean “X is gathered in two kinds of string” (i.e. “X is subsumed under two types”). So much for now.
PS. Interestingly in Sanskrit both sūtra and tantra have the meaning of “string” and so do both mdo and rgyud in Tibetan!