One way to hold barium: a soft silver-white metal that almost never appears on its own. It is so eager to react that people meet it as a compound instead — a white powder in paint, or a white liquid in a hospital. The name points at the substance; the situation tells you which form of it you are dealing with.
Coined by the British chemist Humphry Davy in 1808, from baryta (a mineral name) plus the ending -ium, which English uses for metal elements.
這個名字是英國化學家 Humphry Davy 在 1808 年取的，由礦物名 baryta 加上金屬元素常見的字尾 -ium 組成。所以字面上可以想成「從 baryta 裡取出來的那個金屬」，這也解釋了為什麼這個字一開始就是實驗室裡的字。
Wiktionary entry for barium, supplied in this packet: 'Coined by British chemist Humphry Davy in 1808, from baryta + -ium.'
Two branches
元素本身
這一族就是核心畫面本身：把 barium 當成週期表上的一格來看。
noun · C1
A soft, silver-white metal that is one of the chemical elements. Its symbol is Ba. It is used to make pigments, the dry coloured powders that paints are made from, and its compounds are used in medicine and in industry.
鋇
醫院裡的那一杯
從核心畫面的一個性質長出來：X 光穿不過鋇。既然穿不過，把它鋪在器官內壁上，形狀就會顯現在片子上。醫院用的不是純金屬，而是含鋇的白色液體。
noun · C1
A thick white liquid containing barium that a patient drinks, or that a doctor puts into the bowels, before an X-ray. It coats the inside of the body so that the organs show up clearly in the picture.
鋇劑（照 X 光用）