Translation guide
The English word 'domain' covers several distinct concepts. This guide helps learners choose the right Japanese expression based on the intended meaning, from fields of expertise to internet domains and territories.
Referring to an area of knowledge, study, or professional activity.
The most common and versatile word for 'field' or 'domain' in academic, professional, or general contexts.
彼の専門分野は物理学です。
His domain of expertise is physics.
この分野の研究は急速に進んでいる。
Research in this domain is advancing rapidly.
Often used for 'domain' in the sense of a defined area of knowledge or activity, slightly more formal than 分野. Can also mean 'territory' or 'zone'.
それは私の専門領域外です。
That is outside my domain of expertise.
Means 'scope' or 'range'. Used when 'domain' refers to the extent of something, such as responsibilities or coverage.
この問題は私の担当範囲を超えています。
This issue is beyond my domain of responsibility.
Referring to a domain name on the internet (e.g., example.com).
The direct loanword for internet domain. Universally understood in tech contexts.
新しいドメインを取得しました。
I registered a new domain.
そのサイトのドメインは「.jp」で終わります。
That site's domain ends with '.jp'.
Referring to a physical territory, land, or area under control.
Specifically means 'territory' or 'dominion' in a political or geographical sense.
その国は広大な領土を持っている。
That country has a vast domain.
Historical term for a feudal domain or fief. Used in contexts like samurai territories.
Means 'territory' in the sense of a gang's turf or an animal's territory. Informal and specific.
Referring to a non-physical realm, such as the domain of dreams, the public domain, etc.
Literally 'world', often used to mean 'domain' in a figurative sense, like 'the world of art'.
それは夢の世界の話だ。
That's a story from the domain of dreams.
Also used for abstract domains, like 'the domain of science'.
The set of input values for which a function is defined.
The standard mathematical term for 'domain' of a function.
この関数の定義域は実数全体です。
The domain of this function is all real numbers.
Both can mean 'field' or 'domain'. 分野 is more common for academic or professional fields. 領域 can sound more formal or refer to a bounded area, including physical territory or abstract realms.
彼の研究分野は生物学です。
His research domain is biology.
それは私の専門領域ではありません。
That is not my area of expertise.
The loanword ドメイン is almost exclusively used for internet domains. Using it for 'field of expertise' or 'territory' will sound unnatural.
科学の領域は広大です。
The domain of science is vast.
In the Edo period, feudal lords governed their domains.
あの公園は彼らの縄張りだ。
That park is their domain.
それは科学の領域を超えている。
That transcends the domain of science.