What is the difference between chaete and setae?

The difference between chaete and setae is shown in their structures. Although both terms describe hair like structure in annelids, these terms are used depending on their structure and functions. Setae is a modified cilia while chaetae develope unlike cilia.

That should make it more clear. Its the same thing. Both seta and cheta or chaete means bristles. I think the term can be used interchangeably.