I have noticed this quite often that other (closely) related common nouns are called sister [common noun]. For example:

This question is off-topic here, but is on-topic on our sister site.

This issue can't be resolved here. You will have to visit our sister branch.

Monopoly Casino Sister Sites are listed in here.

ABC is the sister company of DEF.

...and many more.

Why does this kind of phrases/sentences make use of the feminine gender, but never the masculine gender, like brother sites? Did this somehow remotely got influenced by feminism movements? Because looking at this Ngram I can see that such phrases were not present in the old times of 1900 A.D and before.

Any insight on this topic will be warmly welcomed.

P.S: I mean no ill-intention when asking this question or mentioning about feminism movement. This just piqued my interest.

  • 2
    Here is a use of brother: A thing which resembles or is connected to another thing. The machine is almost identical to its larger brother. It lacks a following noun though. Commented Nov 2, 2020 at 19:42
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    I think the Ngrams link just shows us that websites didn't exist in the 1900s.
    – James K
    Commented Nov 2, 2020 at 19:45
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    When it comes to "sister cities" in particular, most nations have traditionally been personified as female. This presumably extends to other entities in human geography, including cities. Commented Nov 2, 2020 at 20:03
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    Also daughter as in daughter cell
    – Void
    Commented Nov 3, 2020 at 6:22
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    For some reason when a rule is changed the process of allowing people who qualified before but may not qualify under the new rule to still be accepted is referred to as grandfathering which adds yet another person to the list.
    – mdewey
    Commented Nov 3, 2020 at 11:47

2 Answers 2


The Oxford English Dictionary shows that this usage goes back to at least the 1500s. It provides the following definition:

Appositive, with the sense ‘fellow’, ‘having a close kinship or relationship to another’; ‘belonging to the same class or group’. In linguistic contexts, denoting a parallel familial relationship (as between languages, dialects, etc.). With reference to places, institutions, etc., sometimes implying a more or less formal link.

Here are some examples of early usage:

  • 1570 J. Foxe Actes & Monumentes (rev. ed.) I. f. 363v/1 A sister Church one with an other, seekyng together ye glory of Christ.
  • 1611 J. Speed Hist. Great Brit. ix. x. 546/1 The right of our noble sister nation.
  • 1641 J. Milton Of Reformation 70 We must..come from Schisme to unity with our neighbour Reformed sister Churches.
  • 1679 J. Fell in J. Gutch Collectanea Curiosa (1781) I. 270 If we are justified, the advantage will extend to our Sister University.

This doesn't answer your question as to why "sister" is used, although if the usage was influenced by French or Latin, "church", "nation" and "university" are all feminine nouns in those languages.

  • Kirche, Universitat, and Nation are all feminine as well. But with all those early references, the Latin example would have been most influential. Commented Nov 2, 2020 at 19:57
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    I think this has less to do with the grammatical gender of these words in Romance languages and more to do with the fact that romantic personifications of places have generally been women: think "Britannia" as the personification of the British Empire. This fell out of style around the time that women got the vote, but the idea that nations/provinces/cities are female is deeply embedded in European history. Commented Nov 2, 2020 at 20:57
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    The reason I suggested gender was that writers were often educated men with a knowledge of Latin (& sometimes French; less commonly German) and may have come across parallel constructions in other languages. But this was admittedly just speculation. The answers at english.stackexchange.com/questions/369932/… are worth a look. I'm doubtful that "sister ship" is the earliest usage. But the most interesting point is that "mother" and "daughter" are similarly used for relationships between entities, never "son", etc.
    – rjpond
    Commented Nov 2, 2020 at 21:14
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    "Sister Church" can have something to do with church being depicted as the bride of Christ throughout the New Testament. 2 John: "The elder unto the elect lady and her children, whom I love in the truth [...] The children of thy elect sister greet thee. Amen."
    – gronostaj
    Commented Nov 3, 2020 at 7:22
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    Thank you for the answer @rjpond. I visited the link you have included here. According to Mari-Lou A's answer, it may have something to do with the ability of females to reproduce. But then again inanimate objects can't really reproduce. So they come from their gender specified nouns, did I get it right? Commented Nov 3, 2020 at 7:22

In describing relations between entities as if they were relations between people, you are personifying those entities. "Sister", "mother", and "daughter" are common because personifications are usually female.

The predominance of females is at least partly because Latin grammar gives nouns for abstractions the female gender.

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    That Wikipedia page doesn't mention language at all, just art, literature, etc. Do you have a reference that this pertains to language as well as art and literature? Commented Nov 3, 2020 at 10:00
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    @T.J.Crowder Literature vs. language is a fine distinction. It seems straightforward to me that literary references to abstract entities using "she", "sister", etc., would filter into everyday speech and writing.
    – nanoman
    Commented Nov 3, 2020 at 19:04

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