cognitive operation of determining, SA rnam gcod, limit, beginning [JV]
determination of the nature [IW]
ngo bo'i cha nas bzhag pa. determination [RY]
determination, conclusion [RY]
yongs gcod is the counterpart of rnam bcad (with "bcad" being the past tense of "gcod"). yongs gcod indicates a positive identification or an affirmation about something, whereas rnam bcad indicates an identification about what something is not; a refutation or negation. So it's kind of like "identification by way of inclusion" and "identification by way of exclusion." (Though I wouldn't suggest those as actual translations to use in an English writing.)
The bod rgya tshig mdzog chen mo (my trans.) says "yongs gcod is a manner in which mind cognizes [an object's qualities]...[it indicates] a cognition by way of affirmation. In the case of a vase, for example,...[a "yongs gcod"] would be the determination that the vase IS impermanent... [A rnam bcad] would be the determination that the vase IS NOT permanent... In the context of the rope-seen-as-a-snake example, the negation of the rope's being a snake is a rnam bcad. The affirmation of the rope's being a rope is a yongs gcod." TBD
If I were to suggest a pair of English standards for these two terms, perhaps "positive determination" for yongs bcod and "determination by way of negation" for rnam bcad.