Recently, people have been using the word "tenor" in advertising to refer to duration. I have looked in several dictionaries and I don't see any definition that would indicate that 'tenor' could be used to indicate duration. However, Investopedia.com has 'tenor' defined as 'The term or life of a contract. Similar to maturity'. Is this American English; is this new English? Can 'tenor' and 'tenure' be used interchangeably? I am confused!
Don't be confused. People who use the word tenor to indicate duration are just wrong. Not stupid, just wrong, pretentious, lazy, ignorant, and did I mention, wrong? Investopedia.com is wrongopedia.com. Further proof that just because you saw it on the internet, doesn't mean it's true. (This goes double for anything I write!)
Buy a good, used collegiate dictionary (made of paper!) for a couple of bucks and trust it.