A watermelon is the big round summer fruit with a hard green skin, bright red flesh inside and black seeds. It is heavy, it is mostly water — which is why it is so cooling — and it is sold in whole ones, halves and slices. Everyone knows this fruit, so the word is completely ordinary.

A watermelon is the big round summer fruit with a hard green skin, bright red flesh inside and black seedswatermelon（西瓜）是一種大又圓的夏季水果，外皮硬又綠，裡面果肉鮮紅、帶黑籽。 It is heavy它很重, it is mostly water而且大部分是水 — which is why it is so cooling這也是它這麼消暑的原因 — and而且 it is sold in whole ones, halves and slices賣的時候有整顆、切半和切片的。 Everyone knows this fruit大家都認識這種水果, so the word is completely ordinary所以這個字完全是日常用字。

A few things about how English handles it. It is one word, no space, no hyphen. It is countable when you mean the whole fruit ('I bought two watermelons') and uncountable when you mean the flesh you eat ('Do you want some watermelon?').

A few things about how English handles it關於英文怎麼處理這個字，有幾點要注意。 It is one word它是一個字, no space, no hyphen中間沒有空格，也沒有連字號。 It is countable when you mean the whole fruit當你指整顆西瓜時是可數名詞 ('I bought two watermelons')（像 'I bought two watermelons'） and而 uncountable when you mean the flesh you eat當你指要吃的果肉時是不可數 ('Do you want some watermelon?')（像 'Do you want some watermelon?'）。

Watermelon juice is a normal thing to say. The green skin is called the 'rind' — a useful word, and the same word used for the skin of cheese and of bacon.

Watermelon juice is a normal thing to sayWatermelon juice（西瓜汁）是很常見的說法。 The green skin is called the 'rind'綠色的外皮叫 'rind' — a useful word這個字很好用, and而且 the same word used for the skin of cheese and of bacon乳酪皮和培根皮也是用同一個字。

There is also a figurative use you may meet in news writing, though it is not common in daily speech: calling someone a 'watermelon' means green on the outside, red inside — that is, someone who says they care about the environment but is really a socialist. It is an insult used in political argument. You do not need to use it, but if you see it, now you know why.

There is also a figurative use you may meet in news writing新聞寫作裡還有一種比喻用法你可能會遇到, though雖然 it is not common in daily speech在日常口語裡不常見: calling someone a 'watermelon' means green on the outside, red inside說一個人是 'watermelon'意思是外面綠、裡面紅 — that is也就是, someone who says they care about the environment but is really a socialist指嘴上說關心環境，骨子裡其實是社會主義者的人。 It is an insult used in political argument這是政治辯論裡的一種侮辱說法。 You do not need to use it你不需要自己用這個說法, but如果 if you see it你看到了, now you know why現在你就知道為什麼了。