What is the difference between 一層, 一段と and より一層?

Question

I know that they all mean "more, much more" but is there any difference between them?

also do they have the same usage as もっと?

Answer 1

もっと、一層, 一段と, より一層, ずっと are almost the same but より一層 and ずっと have more emphasis on "more". Usually, these 5 words can be replaced with another words, but there is an exception.

Here is an example: The following 5 sentences all mean "Is there a better PC?" and they all make sense. The last two sentences use ずっと and より一層, which rather means "Is there a much better PC?"

1. もっといいパソコンはありますか？
2. 一層いいパソコンはありますか？
3. 一段といいパソコンはありますか？
4. ずっといいパソコンはありますか？
5. より一層いいパソコンはありますか？

もっと can be used when you want to ask for more amount of something, or more quantity of something. Say, you want more food. And you want to say "Give me more". The only word is もっと, like "もっとください", but the following sentences don't work.

1. 一層ください。
2. 一段とください。
3. より一層ください。
4. ずっとください。

1 and 2 above doesn't make sense. 3 and 4 can lead misunderstanding because they don't just sounds like "give me more" but also asking to "give me much more than you gave me last time."

Note that 一段 and 一層 have another meanings.

一段 also means a stair. And it also describes the grade of Japanese martial arts like Kendo and Judo. Say, 剣道一段 (Kendo 1st grade) 柔道一段 (Judo 1st grade). By the way, 剣道二段 (Kendo 2nd grade) is better than 剣道一段 (Kendo 1st grade). Same goes to Judo.

一層 literally means "one layer". So it also can be used as "one layer" rather than "more". Say, some window glasses have two layered structure that has two glasses and air between to keep the room warm. That kind of window can be described 二層構造(two layered structure) and the one only has one layered window glass can be described 一層構造(one layered structure).