Why is not cucumber considered as a testing tool?

I'm new to Cucumber, and I'm trying to understand the tool. While reading the documentation, I found that it is defined shortly as "a tool that supports BDD":

Cucumber is a tool that supports Behaviour-Driven Development(BDD).

Also it is described as a "validation tool":

Cucumber reads executable specifications written in plain text and validates that the software does what those specifications say.

In the other side, I noticed the excessive use of the word "test" on the 10-minute tutorial.

AFAIK, this tool is used massively in integration tests and acceptance tests.

Now if this tool is not really about testing, then what other possible usages can be expected?