When you enter a physical store, you have tables above aisles that denote the category of products that are being sold in particular section.
The online equivalent of this are the product paths that show the main category, subcategory, level 3 category, and so on. In earlier days of internet these categories were set manually but with Amazon now selling millions of products, the product categorization has been automated in the meantime, using the machine learning and AI models for this purpose. There are millions of niches available for products to sell.
All one needs for training a ML model is a good training data set in the form of product name -> categories and then one can train an appropriate text classification model.
Regarding possible categories, there are two main options. One is Google Product Taxonomy and the other is IAB classification, both have Tier 1, Tier 2 and lower Tiers of categories.
For ecommerce product categorization, the more appropriate is the Google product taxonomy categorization, whereas IAB is more general and has gone through several revisions.
An excellent Saas platform that offers product categorization is Productcategorization.com. You can try out their demo at this address:
https://www.productcategorization.com/demo_dashboard/
It gives the output in form of nice chart as well as json file that can also be exported.
Another important version of categorization involves tagging of products. This is a more modern version of trying to classify the products and has the added benefit that there is no general upper limit on number of tags that can be assigned to products of online ecommerce shop.
A solution offering product tagging is available at producttagging.com. You can try out demo of product tagging at:
https://www.producttagging.io/demo_dashboard/
I tried diamond earring and got these tags (with percentages denoting how relevant is the tag for the product name):
2 %
If you are interested in learning more details on theoretical background to product categorization, check out an article on this topic:
https://medium.com/product-categorization/product-categorization-introduction-d62bb92e8515
Interesting collection of slides on the topic of product categorization: https://slides.com/categorization
Product tagging and categorization have a bright future with number of online shops rapidly increasing.
Another text, more general text classification problem is website categorization.