Unlike morphological change, SEMANTIC CHANGE cannot be reduced to neat schemes like those in §14. Changes in form are governed, to some extent, by dependable phonetic laws; changes in meaning, on the other hand, result from social and cultural influences that may be absolutely unique. Scholars have identified and labelled several categories of semantic change, but we shouldn’t expect to squeeze every shift of meaning into one of these pigeonholes.
A word’s original meaning may be extended or enlarged, so as to have a wider semantic application than was originally the case. In Latin a discus was a specific athletic device; the derivative disc (or disk) may refer to anything round and flat. Augustus Caesar built a grand home on the Palatine hill that was called the Palatium; centuries later, the word palace denoted any royal or noble residence—just as Caesar (> czar, Kaiser) came to mean any autocratic ruler.
The opposite semantic change occurred even more often in the development of English vocabulary from Latin. Time and again we meet English derivatives that have a much narrower meaning that their Latin source-words. Latin fabula was any kind of story, whereas English fable is more limited in scope. Latin pulpitum was simply a platform or scaffolding; English pulpit is a special structure in a church. The sermon delivered from the pulpit is more specialized than its Latin source-word sermo (3rd declension), which meant “a conversation.”
3. METAPHORICAL EXTENSION:
In many cases of semantic change, it is hard to say whether the derived meaning is broader or narrower than the original; the word seems rather to have acquired a figurative or metaphorical force. A stimulus was a goad or spur; the English term refers to a metaphorically sharp incentive that rouses us to action. A radius was, among other things, the spoke of a wheel (a meaning very close to its literal application today in geometry); the derivative ray can be viewed as a figurative spoke—though one could argue equally well that this is a case of generalization. One of the best examples of metaphorical extension is focus, which evolved from an original meaning of “hearth” or “fireplace.”
4. AMELIORATION and PEJORATION (also called ELEVATION and DEGENERATION):
Don’t be cowed by these intimidating labels, which come from the Latin comparative adjectives melior (“better”) and pejor (“worse”). They describe semantic changes as a result of which the original word has either improved or deteriorated in meaning. AMELIORATION can be illustrated by the word minister—in Latin, a lowly servant or attendant, but in English a respected clergyman or senior politician. Again, the Latin adjective nescius (“ignorant”) has been substantially elevated in becoming nice. PEJORATION or degeneration of meaning was already evident in Latin idiota (“uneducated person”), which had begun life as the very respectable Greek word idiōtēs (“private person,” “individual”—compare E idiosyncracy); the English derivative idiot has sunk even lower in semantic respectability. A similar fate overtook the word peculiar, which meant “one’s own” in Latin.