Ownership comes after a lengthy legal battle with Twittad.
Social network Twitter and Twittad have been embroiled in the tweeting trademark tangle for years.
Twitter argues the term 'tweet' was famous as a Twitter expression before Twittad trademarked it, but courts have disagreed.
Twittad provides sponsored advertising for Twitter and its tagline 'Let me add your tweets' is trademarked along with numerous versions including the word 'tweet.'
The two companies have now resolved the dispute and as part of the settlement, Twittad will transfer the 'tweet' trademark to Twitter, but will use its current trademark, according to Wall Street Journal.
Lynn Fox, Twitter spokesperson, said: "We’ve arrived at a resolution with Twittad that recognises consistent use of Tweet while supporting the continued success of Twitter ecosystem partners like Twittad."
Whether money changed hands to seal the deal is unknown but James Eliason, CEO of Twittad, said: "The moral of the story is to make sure you trademark and patent-protect everything."