1. A series of tweets on a particular topic composed by an individual Twitter user and posted in succession. Each tweet may start with number and a slash (such as "2/4") to convey that it is part of a longer message. Good grief, did you see her latest tweetstorm? I don't need eight tweets from one person clogging up my feed!

2. A surge in activity on Twitter as users comment on a particular topic or current event, often one that is controversial. Such users commonly use a unique hashtag relevant to the topic. The actor's sexist comments sparked a real tweetstorm, as well as a public outcry.