When I say "Tweet", do you think of Twitter?
Twitter has a US registered trademark for TWEET for downloadable computer software, telecommunication services, blogs, and social networking.
A company filed a trademark application for TWEET for birdseed. Twitter opposed the trademark application on February 19, 2021 (see TTABVUE link). In its Notice of Opposition, Twitter states that its TWEET trademark is famous (see page 5), and that therefore no one else can use the trademarked term.
I look forward to seeing whether the Trademark Trial and Appeal Board agrees with Twitter's position.