[michael-ax]

Have you ever tried to trademark a random noun?

[marcinzm]

No but lots of other people have: https://tmsearch.uspto.gov/search/search-results

Feel free to release a computer named Apple to prove me wrong.

[michael-ax]

Alright, read up on domains, then try arguing that 'perplexity' as company and noun are in different spaces! I grant you that if they were, the company could trademark that noun. But it seems clear that Perplexity named itself after the noun and by so doing gave up the option of trademarking its company name.