Keyword classifications include i) general comprehensive classification, ii) concept classification, and ii) purpose-solution classification (coming soon).

https://whimsical.com/en-2f1ADrz8pgTxs3ykW6xA4u
A word differs from a keyword in that it is composed of a single word. For example, "bluetooth low energy" is a keyword. The individual words that make up this keyword - bluetooth, low, and energy - are words. If "bluetooth low energy" were recognized as an individual word, this keyword could also be connected to oil(because of energy). Key
General comprehensive classification is a versatile classification scheme that can serve most classification purposes.
https://whimsical.com/en-GovVkr3zM1U5Ubokgj3DHh
Concept classification is about technology solutions and systems of thought. Concept classification, when utilized well, allows you to read thoughts from the target information object.
Purpose-solution problem classification is about the technology challenges and problems you want to solve.
PatentPia has assigned a 1:1 generic unified classification to each of the 8 million keywords it handles, which reduces complexity and increases convenience and intuitiveness.
PatentPia has assigned 1:1 concept classification for more than 1 million keywords it handles.
https://whimsical.com/en-8XWTuPpCbhQpv9nZa7eJTv
By utilizing keyword classification, you can extract only the keywords for your purpose from a large number (100-2000+) of keyword lists (e.g., polymeric material keywords among materials/materials, sensing and measurement related keywords among products-materials, etc.).
By applying classification and time sorting to keywords, one-click technology sensing or alerts are possible, etc.
From a functional view, filtering has a lot in common with search.