General:
* Practicality: This is the most direct noun form, meaning the quality of being practical.
* Usefulness: This emphasizes the value or benefit of being practical.
* Applicability: This refers to the ability of something to be applied in a practical way.
More specific:
* Tool: If you're talking about a practical object, "tool" can be used.
* Method: If you're talking about a practical way of doing something, "method" can be used.
* Solution: If you're talking about a practical answer to a problem, "solution" can be used.
The best noun to use will depend on the specific context of your sentence.
For example:
* "The practicality of her approach impressed me."
* "The usefulness of this tool is undeniable."
* "The applicability of this theory to real-world situations is limited."