Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “subject line”

subject line

noun [C]
the short line at the top of an email that tells you the subject of the message: State law requires that the emails include "ADV" in the subject line.
(Definition of subject line from the Cambridge Business English Dictionary © Cambridge University Press)
What is the pronunciation of subject line?
Add Cambridge dictionaries to your browser to your website

Word of the Day


a measure for liquid equal to about half a litre

Word of the Day


Read our blog about how the English language behaves.

Learn More

New Words

Find words and meanings that have just started to be used in English, and let us know what you think of them.

Learn More