基础词的英文：
underlying word

underlying adj.
在下面的；优先的；基础的；潜在的

Shale underlies the coal.
页岩层在煤层下面。

This word has its underlying meaning.
这个单词有它潜在的含义。

The underlying reason for the failure remains unknown.
失败的根本原因尚未搞清。

Open the underlying adapter for retrieving packets.
打开优先的适配器用于接收数据。

There is an
在apple这个词中有一个字母A。

This is a derivative word.
这是一个衍生词。

This is an informal word.
这是一种口语用语。

Bitter words and good acupuncture—to advise with faithful words.
苦语针砭。

The German word `Haus' is cognate with the English word `house'.
德语的haus一词和英语的house一词同源.