单词：word
来源：Old Engpsh "weord"

例句：

Can you spell that word for me?
请你把那个单词拼写给我？
She has a vast vocabulary and knows many words.
她的词汇量很大，知道很多单词。

句子：sentence
来源：Late Latin "sententia"

例句：

That is a grammatically correct sentence.
那是一个语法正确的句子。
She wrote a sentence in her journal every day.
她每天在日记里写下一个句子。