A tag is a keyword or label that categorizes your question with other, similar questions. Using the right tags makes it easier for others to find and answer your question.

used for questions that ask users to discuss an idea, concept, or problem in an abstract way. A discussion question may not necessarily have a clear-cut right or wrong answer and is often…
5261 questions
A request for assistance with one of the site's features.
2341 questions
used to write mathematics on Stack Exchange sites.
909 questions
You have an idea for a new feature on the site, or for a change to the existing functionality.
Indicates a reproducible problem on the site that you believe is due to a mistake, malfunction, or programming error.
keywords or labels that categorize and group your question with other, similar questions. If your post at meta is about suggesting new tags, choosing correct tags for some question, suggestin…
when asking what is on- or off-topic on the main site, and why.
when you want to draw attention to a specific question on the main site. For example, if you want to draw high-rep users to close/reopen/edit a question, if you want to discuss the…
small addendums to each question or answer, intentionally limited in size and formatting.
a core, fundamental Stack Exchange value -- we allow editing by registered and unregistered users (if peer reviewed).
will be used to ask questions dealing with reputation.
For questions about the /review path where users can view and act on posts by other users that the system thinks may need attention.
for questions about answers on the main site. Consider using the accepted-answer tag if the question is about an answer that has been accepted.
Indicates that the report has been resolved through the implementation of a feature or the fixing of a bug.
262 questions
The process by which users can vote a question closed if it is off-topic or otherwise disallowed by the FAQ.
Questions specifically about the process of asking questions on this site.
the community's way of telling peers that their content can be improved. Downvotes on meta may have different meanings.
the process of bringing a question, answer or comment to a community moderator's attention for any reason.
for questions about questions, answers and comments that have been deleted, or nominated for deletion.
referring to the process of identifying and closing questions that are exact duplicates of another question.
aimed for discussions about etiquette: how to behave on the site and the chat.
Users without full edit privileges can suggest edits to posts and tag wikis
196 questions
a way to get additional attention for a question by offering some of your own reputation for great answers.
For instructions and guidance on closing or migrating questions, and the reasons for those closures.
refers to all questions deleted from Stack Exchange sites. The tag 'specific-question' should also be used when referencing a specific question that has been deleted.
the primary way users gain reputation, and also how many items are sorted to the top.
159 questions
For questions about built-in search functionality of this site and about searching this site using external search engines.
The user interface elements and web pages that make up this site.
147 questions
awarded to encourage and incentivize positive community actions within the site.
For questions concerning the management of tags on both the main site and meta. Common topics include the merging of tags, and making tags synonyms of one another.
136 questions
Questions about diamond (♦) moderators, their powers, and actions they have taken.
132 questions
the answer the question owner thought best met their needs. Accepting is encouraged but never required. This tag is for *discussing* issues related to accepted answers, not indi…
124 questions
for questions on Mathematics Stack Exchange policies
119 questions
For questions concerning using images in questions, image hosting etc.
Refers to user accounts either generically, or across the network.
108 questions
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