a word or phrase that is listed separately with its own definition, examples of use, etc. in a dictionary or similar book

The headwords are in bold dark blue type. 词目用的是深蓝色的粗体字。

"Hard line" is not covered under "line" but is a headword in its own right. “Hard line”本身就是一个标题词，并不包括在“line”之下。