Why's "a thousand questions" instead of just "thousand questions?" Why's "a" necessary?

Native speaker’s answer
Rebecca
"A thousand questions" means "one thousand questions," the "a" means "one." It wouldn't sound natural to say "thousand" on its own since there's no indication of how many thousands. Here "a thousand" just means "many." Ex: There are thousands of reasons why I don't want to go tonight. => "thousands" means numerous thousands, not just one thousand. Ex: They've invited a thousand people to their wedding. => one thousand people