"sister-site": noun gender

Question

After spending some time on the English SE, I noticed that everytime someone referred to ELL, they always did so by saying "our sister-site ELL".

As I understand, there is no grammatical gender in English. For example, dictionaries do not specify any gender, even for nouns clearly gender related like woman.

Someone said in an answer "We divide things into male people, female people, and everything else.". A website is in the "everything else" category. How come the word that is used before site is sister, and not brother or a mix of both or even a gender-neutral word?

Related links:
Does the English language have a grammatical gender? (ELL)
Grammatical gender of the word “child” (ELL)
Does standard English support gendered forms of nouns and verbs? (ELL)
Nouns and gender (Cambridge)

Answer 1

A very astute observation! Yes, English technically has no grammatical gender in the sense that nouns are not grammatically masculine/feminine/neuter/etc. However, we do occasionally refer to inanimate objects as if they were animate and gendered, usually female.

Sister in a case like this means "related as if by sisterhood". Why "sisterhood" and not "brotherhood" or just "siblinghood"? It's hard to say, except that we have this tradition of referring to objects as female; it may stem from the fact that historically, ships have been called she, so ships of the same design were regarded as "sisters".

Probably the most common examples of using sister to refer to related things are:

• Sister ships (ships that are of the same design and are nearly identical to each other)
• Sister cities (cities that have entered into an agreement to promote closer cultural and commercial ties between them)

So ELL and ELU are sister sites because they share the same origin and the same design, like ships.