grammar of a sentence explaining a 四字熟語{よじじゅくご}

Question

I read here the following explanation about 一朝{いっちょう}一夕{いっせき}, a 四字熟語{よじじゅくご} :

一日や半日{はんにち}、朝{あさ}から夕程度{ゆうていど}の、短{みじか}い期間{きかん}のこと

I don't feel confident about the grammar in this sentence, specially about the の particle after 夕程度{ゆうていど} : does the whole sentence mean something like "a short gap of time during one day or half, roughly from the morning to the evening" ?

Is the の the "explanatory" particle ? And why don't we read 朝{あさ}から夕{ゆう}まで ?

Answer 1

［一日や半日］［［朝から夕程度の］［短い］期間］のこと
"a half or full day; a morning-to-evening-scale, short time interval"

1. The の in 朝から夕程度の can be understood as である.
2. The comma after 朝から夕程度の makes it so that 朝から夕程度の and 短い are two separate ways of describing the interval, as opposed to further refining the type of "short time interval" it is. (Imagine removing the comma after "morning-to-evening-scale" in my gloss.) The difference in nuance is subtle, but basically with the comma it sounds more like the entry is expressing the complexity or vagueness of the concept because it needs to use multiple different modifiers to describe it.
3. 朝から夕まで would refer to the exact time interval of morning to evening. 朝から夕程度 is a morning-to-evening sized interval.

Answer 2

Well, first off, that's not really a complete sentence, it's just a brief definition. This grammar is everything up to the の modifies the 短い期間 which by itself is already pretty good defintion. The commas like in English is just reiterating or defining the same thing, so in this case it's like saying:

A small period of time such as from morning to evening; a day or half-day

I find with words it's useful to search for example sentences, in Japanese 例文, there are some good ones here:

http://dictionary.goo.ne.jp/leaf/thsrs/15090/m0u/