What would be considered a niche?

Is "fly fishing" a niche, as it is narrowed down from just "fishing"? Or is "fly fishing in Brisbane, Australia" closer to what the term is?

Or say an online store that sells digital products only (range of products that are only delivered digitally) on a broad topic such as interior design. Is that a niche because it is selling specific types of products for a broad topics?
Or would the actual topic be narrowed down to a small interest area is well?

Thank you. :)
(and no I'm not selling interior design digital products, heh)Fly fishermen/women would be a niche and narrowing them down to being based in Brisbane is a tighter niche. A niche is usually the market that you target rather than the product you're promoting.

Your example of interior desing digital products, therefore, is not a niche. The niches for those products would be interior design students or whoever you consider the target market.

In our business we offer training courses in marketing, as do lots of companies. We target niches such as Art Galleries, Picture Framers and Bed & Breakfast owners. We further narrow it down to specific geographic areas, such as London, Manchester and Glasgow.