What term describes a product that has not been available before or bears little resemblance to an existing product?

The term that describes a product that has not been available before or bears little resemblance to an existing product is "new product." This term refers specifically to innovative offerings that either introduce a completely novel solution in the marketplace or apply a unique approach that significantly differentiates it from existing products.

New products can emerge from technological advances, new findings in consumer behavior, or shifts in market demand that create opportunities for entirely new categories. In contrast to incremental enhancements, which involve minor improvements to existing products, or additions to existing product lines, which build upon established offerings, a new product introduces something fundamentally distinct. It can also be contrasted with repositioning, where existing products are marketed in a new way rather than being created from scratch.

Thus, the focus on innovation and major differentiation from existing products confirms that "new product" is the correct definition in this context.