What is the difference between sub- and hypo-?

Answer 1

sub- simply means under , but hypo- is to minimize a thing , like "hypofunction" which means reduction in function , an other e.g. is hypothalamus in the human brain , it means a small thalamus , thalamus is an other structure in the brain but larger than the hypothalamus , so that the idiom hypothalamus , I think "hypo-" is used wrong in medicine , in the meaninig of under , like " hypoglossal nerve" and the wanted meaning is " under the tongue " and most medical references talk about hypothalamus as it is under the thalamus not as a structure smaller than the thalamus , and you don't find "hypo" in the medical dictionary in the meaning of "under " but in the meaning of "reduction or smaller " .

Answer 2

From what I've read (within the past 5 minutes of research), it just appears as though "Hypo-" was appropriated from the Greek language, and "Sub-" was appropriated from the Latin language.

It appears they were used in either language to mean (generally) the same thing; the English language just couldn't agree on which Indo-European language it should take this morphograph from, so it chose both.

The English language does this quite often since it is an amalgamation of multiple Indo-European Languages (partially Germanic, Latin and Anglo-French).

However, when it comes specifically to Greek morphological appropriation, it is most commonly done in English by specific fields, typically in academia, to form a more distinct system of nomenclature.

This is why you may see the prefix "Hypo-" being used more often in chemistry, Biology and other sciences, whereas the prefix "Sub-" may be used more ubiquitously in common terminology.