[Each word each day, maybe] Thread

As a programmer, of course, I'm very familiar with this word . But sometimes, when I look up some English words in some English search engines such as google in english or bing in the United State, I access some forums where I meet this word 'Thread' too. It's used to describe all the discussion of one topic.

And I found the definition of 'Thread' in the dictionary of Bing.

discussion on Internet: a series of messages in an Internet discussion groupforum, commenting on or replying to a previous message.