What is the difference between 密閉 and 気密?


Both are used to mean "sealed airtight".

気密 is a Noun, while 密閉 can also be used as a suru verb "to seal airtight"

Apart from these, is there any meaningful difference?




[dictionary.goo.ne.jp entry for
密閉](https://dictionary.goo.ne.jp/srch/all/%E5%AF%86%E9%96%89/m0u/):

> みっ‐ぺい【密閉】
>
> ［名］(スル)すきまのないように、ぴったりと閉じること。「容器を―する」

Translation (mine): **To be closed, such that there are no gaps. "(seal) a
container"**

[dictionary.goo.ne.jp entry for
気密](https://dictionary.goo.ne.jp/srch/all/%E6%B0%97%E5%AF%86/m0u/):

> き‐みつ【気密】
>
> 密閉して気体の流通を妨げ、気圧の変化の影響を受けないようにすること。「―構造」「―性が高い」

Translation (mine): **To be sealed in order to prevent the circulation of
gases or be unaffected by changes in atmospheric pressure.**

Note that the definition of 気密 actually uses the term 密閉. So 密閉 really just
means "seal" (close something so that there are no gaps or cracks, etc).
Whereas 気密 is a sub-category of 密閉 where something is explicitly sealed (密閉した)
in such a way that it is also totally airtight.

密閉 could be used in situations where in English we might use "airtight" in a
figurative sense (i.e. "The security was airtight", etc), but it does not
_literally_ mean "airtight", it only really means "sealed tightly". On the
other hand, 気密 actually literally means that no air (or other gasses) can get
in or out.




[dictionary.goo.ne.jp entry for
密閉](https://dictionary.goo.ne.jp/srch/all/%E5%AF%86%E9%96%89/m0u/):

> みっ‐ぺい【密閉】
>
> ［名］(スル)すきまのないように、ぴったりと閉じること。「容器を―する」

Translation (mine): **To be closed, such that there are no gaps. "(seal) a
container"**

[dictionary.goo.ne.jp entry for
気密](https://dictionary.goo.ne.jp/srch/all/%E6%B0%97%E5%AF%86/m0u/):

> き‐みつ【気密】
>
> 密閉して気体の流通を妨げ、気圧の変化の影響を受けないようにすること。「―構造」「―性が高い」

Translation (mine): **To be sealed in order to prevent the circulation of
gases or be unaffected by changes in atmospheric pressure.**

Note that the definition of 気密 actually uses the term 密閉. So 密閉 really just
means "seal" (close something so that there are no gaps or cracks, etc).
Whereas 気密 is a sub-category of 密閉 where something is explicitly sealed (密閉した)
in such a way that it is also totally airtight.

密閉 could be used in situations where in English we might use "airtight" in a
figurative sense (i.e. "The security was airtight", etc), but it does not
_literally_ mean "airtight", it only really means "sealed tightly". On the
other hand, 気密 actually literally means that no air (or other gasses) can get
in or out.

