What does it mean when someone says hash tag?

[Monkey]

[Chris]

It literally means this ----> #
It is the initial symbol for a Twitter comment.

[Katie]

This is a hash tag: #
In everyday conversation, people usually use it to refer to a Twitter trend.

[Hannah]

a hash tag is this symbol: #
if someone talks about them it could be a reference to twitter, where people put hash tags before topics to help categorize their tweets so they show up easily in twitter searches.

[London man]

hash tag - #

Hope this helps.