General way to describe words like "understand", based on archaic senses of their component parts

The word "understand" is fascinating. A surface parse of the word gives little insight into how the components are related to the concept associated with the word. In contrast, with words like "leftover", it's not hard to figure out the link between the pieces and the concept ("left" makes sense, in that some part of the whole was "left", and "over" because the part that was left is "over and above" the part that was used). But "understand" is harder. As it turns out, "under" is used in a sense that no longer applies its usage in "understand", with the concept of "among" or "inter". So "understand" means something like "standing in the midst of" the thing that is understood.

My question is, is there a general way to describe such a phenomenon, where words are made of components that no longer have the meaning that led to their usage as such a component? Does this phenomenon have a name, or associated body of study?

Solution 1:

Etymology is the name of the field of study for how words change their meanings over time.

All words are composed of at least one morpheme. A morpheme is the smallest part of a word that carries meaning. For example "smallest" has two morphemes: "small" and "-est", and "word" has only one morpheme: "word". Morphemes are atomic because they no longer carry their meanings if they are reduced any further.

Etymology tells us where words come from, it doesn't tell us what words mean today as words often change their meanings from what they meant in the past.

So for "understand" we have a word that has the morphemes "under-" and "stand". However, it doesn't mean "to stand under", it means "to comprehend". The meanings of both morphemes have drifted so much that we no longer understand (ha!) or recognise their ancient meanings, while the word as a whole has a meaning not hinted at by its constituent morphemes.

This is what etymology is for: to make sense where the history based on the present meaning is obscured.