Highest — at the very top of something, with nothing above it.

Highest最高的，at the very top of something在某個東西的最頂端，with nothing above it上面沒有別的東西了。

It is an adjective, and it sits in front of a noun: the topmost branch, the topmost shelf, the topmost floor of the building. You would not say "the branch is topmost" — English speakers keep this word before the noun, not after the verb be. It is a little more literary than everyday speech; in conversation people usually say "the top branch" or "the highest shelf".

It is an adjective這是一個形容詞，and it sits in front of a noun要放在名詞前面：the topmost branch, the topmost shelf, the topmost floor of the building像the topmost branch最頂端的樹枝、the topmost shelf最上層的架子、the topmost floor of the building大樓最頂層。You would not say "the branch is topmost"你不會說「the branch is topmost」這種話——English speakers keep this word before the noun英文母語者會把這個字放在名詞前面，not after the verb be而不是放在be動詞後面。It is a little more literary than everyday speech這個字比日常口語稍微文言一點；in conversation people usually say "the top branch" or "the highest shelf"平常講話大家通常會說「the top branch」或「the highest shelf」。

You will meet topmost most often in writing — stories, descriptions of buildings and mountains, and technical writing about layers (in computer drawing programs, the topmost layer is the one that covers all the others).

You will meet topmost most often in writing你最常在文字裡碰到topmost這個字——stories, descriptions of buildings and mountains像小說、描寫建築物和山的文章，and technical writing about layers還有講圖層的技術文章（in computer drawing programs在電腦繪圖軟體裡，the topmost layer is the one that covers all the othersthe topmost layer最上面那一層就是蓋住其他所有層的那一層）。

The -most ending is doing one job: it pushes the word to the extreme end of the scale. English has a small family of these: innermost, outermost, uppermost, foremost, hindmost, rearmost. They all mean "the very ___-est one".

The -most ending is doing one job-most這個字尾只做一件事：it pushes the word to the extreme end of the scale它把這個字推到量表的最極端。English has a small family of these英文有一小群這樣的字：innermost, outermost, uppermost, foremost, hindmost, rearmostinnermost最裡面的、outermost最外面的、uppermost最上面的、foremost最前面的、hindmost最後面的、rearmost最後方的。They all mean "the very ___-est one"它們的意思都是「最那個___的那一個」。

Note that topmost and uppermost mean almost the same thing, but uppermost is also used for ideas — "that question was uppermost in my mind" — and topmost is not.

Note that topmost and uppermost mean almost the same thing要注意topmost和uppermost意思幾乎一樣，but uppermost is also used for ideas但uppermost還可以用在想法上——"that question was uppermost in my mind"像「that question was uppermost in my mind那個問題在我腦中最優先」這樣——and topmost is nottopmost就不行這樣用。