土裡的那顆紅根
這一支就是顏色的來源本身：那顆可以煮、可以醃、可以榨汁的根。
noun · B1
A round vegetable with a dark red root, which is cooked, pickled, grated raw into salads, or made into juice. This is the British English word; American English usually says beet.
甜菜根
核心畫面
One way to hold beetroot is to picture the colour rather than the vegetable. A heavy round root comes out of the ground, and the moment it is cut everything near it takes that deep purple-red: fingers, the board, the water in the pan, the rest of the salad. Every use of the word is that colour arriving somewhere it cannot be wiped off — including on a face.
beetroot 可以想成先記顏色，再記蔬菜。一顆圓圓重重的根從土裡挖出來，一切開，旁邊的東西就全被染上那種很深的紫…更多收起
beetroot 可以想成先記顏色，再記蔬菜。一顆圓圓重重的根從土裡挖出來，一切開，旁邊的東西就全被染上那種很深的紫紅：手指、砧板、鍋裡的水、整盤沙拉。這個字的每一種用法，都是那個顏色跑到某個地方、而且擦不掉——包括跑到一張臉上。From the word’s history
Wiktionary gives it as beet + root: the root of the beet plant. That is also why American English can simply say beet — both names point at the same plant, and the British one just spells out which part you eat.
Wiktionary 記的是 beet 加 root，也就是「甜菜的根」。這也說明了為什麼美式英文直接說 beet：兩個名字指的是同一種植物，英式只是把「吃的是根」這件事講出來。
Wiktionary entries for beetroot (noun and verb), etymology_text: From beet + root (kaikki:3f6f69a190036ae4:932469348 / :932505043)
Two branches
臉上的那個紅
同樣的深紅，只是這次出現在臉上，而且一樣是你擋不住、擦不掉的。
noun · B2
To go beetroot is to turn bright red in the face, especially because you are embarrassed. It is informal British English, and it compares the colour of your face to the deep red of the vegetable.
臉紅得像甜菜根