I thought that the meaning of nying in words such nying lag, nying sprul, and nying mtshams sbyor ba is clear and self-evident but I am quite surprised to see that it was not at all clear to Jäschke. His, so to speak, docta ignorantia surprises me! Without having delved into primary and secondary sources, I would think, nying simply means “two” (from gnyis) as in nying mtshams sbyor ba (lit. “fusion of the two”) or “secondary” as in nyin lag, which may be rendered as “secondary branches” as opposed to yan lag “(primary) branches.” The use of nying may be a bit comparable to the use of yang (as in yang ’jug). What about nying in nying khu? If we understand khu as “juice or essence,” then nying khu would mean “essence of the essence,” i.e. quintessence.