61869
According to my dictionary they both mean "ocean", but I guess there is a
reason for both words to exist. Am I right ?
CC BY-SA 4.0
2018-09-29T22:55:01.293
61860
2018-10-08T19:34:21.583
2018-10-08T19:34:21.583
19357
29500
question
word-choice words
What's the difference between 海洋 and 大洋?
They both mean "ocean" indeed but because of 大, 大洋 makes a listener think of
big vast ocean, whereas 海洋 covers all kinds of seas big and small, such as
海洋生物 (marine life) or 海洋資源 (marine resources)
CC BY-SA 4.0
2018-09-30T00:39:36.453
61865
2018-09-30T00:39:36.453
3059
61860
answer
海洋 is simply a technical/scientific version of 海. In scientific contexts, 大洋
specifically refers to the five [**global
oceans**](https://en.wikipedia.org/wiki/World_Ocean) on the earth, namely 太平洋
(The Pacific Ocean), 大西洋 (The Atlantic Ocean), インド洋 (The Indian Ocean), 北極海
(The Arctic Ocean), and 南極海 (The Southern Ocean). Imagine 大洋 is a oceanic
version of 大陸 (continent). See [this Wikipedia
article](https://ja.wikipedia.org/wiki/%E5%A4%A7%E6%B4%8B).

Outside scientific contexts, 大洋 is not a common word. It's possible to use it
simply in the sense of "big ocean", but I think 大海 is much more commonly used
for this purpose.
CC BY-SA 4.0
2018-09-30T02:27:35.837
61869
2018-09-30T02:27:35.837
5010
61860
answer
Basically agrees with Naruto’s answer. Here is an explanation from
kotobank.jp:

> 海洋 かいよう ocean
>
> 地球表面の陸地以外の水をたたえた凹所で，水は塩分の組成が一定の海水である。海洋の総面積は約 3.6億km²で，陸地の約
> 2.4倍。海洋は大洋と付属海に分けられる。大洋は面積が広く，独立の海流系をもつ海で，太平洋，大西洋，インド洋の三つに分けることが多い。付属海は大洋の海流の影響を受ける海で，浅くて独立の海流系がない。付属海は地中海と縁海に二分される。

Therefore 海洋 means _ocean_ , as opposed to _land_ , and it includes 大洋
(Pacific, Atlantic, etc.) and 付属海 (adjacent sea).
CC BY-SA 4.0
2018-10-01T00:22:41.913
61890
2018-10-01T01:14:46.317
2020-06-17T08:18:27.500
-1
31428
61860
answer