Meaning of the word "subject line" in English

What does "subject line" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

subject line

US /ˈsʌbdʒekt laɪn/
UK /ˈsʌbdʒekt laɪn/
"subject line" picture

Noun

1.

the line of text that appears in an email, indicating the topic of the message

Example:
Please make sure to include a clear subject line in your email.
A good subject line can increase the open rate of your emails.
Learn This Word at Lingoland