Meta descriptions are HTML attributes that provide concise explanations of the contents of web pages. Meta descriptions are commonly used on search engine result pages (SERPs).
Metadata(Data about Data) element used to provide structured metadata about a Web page. Multiple elements are often used on the same page.
Meta descriptions can be any length, but search engines generally truncate snippets longer than 160 characters. It is best to keep meta descriptions between 150 and 160 characters.
Example :-
Note :- Avoid Duplicate Meta Description Tags
Google Old Metadata Character Limits :-
New Google Metadata Character Limits :-