A brainchild is not a child. It is an idea, a plan, a product, a club, a festival, even a whole company — something one person thought up without waiting for a committee, as if the idea were born from their mind. The feeling is “this was theirs; they did not copy it.” We say “the festival was her brainchild” or “the brainchild of Mr Chen.” You will meet this in news, business, and everyday talk: a little colourful, not slang, and not a cold legal word.

A brainchild brainchild is not a child不是小孩. It is an idea, a plan, a product, a club, a festival, even a whole company它是一個點子、一個計畫、一項產品、一個社團、一個活動，甚至是一整間公司 — something one person thought up without waiting for a committee是一個人自己想出來的東西，不用等委員會決定, as if the idea were born from their mind好像這個點子是從他腦子裡生出來的一樣. The feeling is "this was theirs; they did not copy it"這種感覺是「這是他們自己的；不是抄來的」. We say "the festival was her brainchild" or "the brainchild of Mr Chen"我們會說「the festival was her brainchild」或「the brainchild of Mr Chen」. You will meet this in news, business, and everyday talk你會在新聞、商業和日常對話裡碰到它: a little colourful, not slang, and not a cold legal word帶點生動的感覺，不是俚語，也不是冷冰冰的法律用詞.

If many people built the thing together, brainchild is a stretch, unless one person clearly had the first spark.

If many people built the thing together如果是很多人一起打造出來的東西, brainchild is a stretch用 brainchild 就有點勉強, unless one person clearly had the first spark除非明顯是某一個人先有了那個火花.

You will almost always meet it as a noun. A few writers use it as a verb, to brainchild something, meaning to think it up — but that sounds odd to many ears, and the noun is the one worth learning.

You will almost always meet it你幾乎都會看到它 as a noun當名詞用. A few writers use it as a verb有些作者會把它當動詞用, to brainchild something, meaning to think it upto brainchild something，意思是想出某個東西 — but that sounds odd to many ears但這種用法聽在很多人耳裡怪怪的, and the noun is the one worth learning值得學的是名詞用法.

Though actually, once the idea has grown and other people run it, speakers still call it the first thinker’s brainchild, as if the “child” had grown up and walked away.

Though actually不過事實上, once the idea has grown and other people run it即使這個點子後來長大了、換成別人在經營, speakers still call it the first thinker's brainchild大家還是會說它是最初那個人的 brainchild, as if the "child" had grown up and walked away好像那個「孩子」已經長大、自己走開了一樣.