I'm not saying there a cruel thing to use. Ours never really took to one but I know some dogs do. But if you asked a member of the public they'd describe it as a cageWe used a crate for our pup.....first night at home she slept in the crate in our bedroom then slowly over the next few nights moved it out onto the landing then downstairs. She's happy as can be in the crate, it's her bed/cave.
We now use it in the van and she travels for hours secure in the crate.