Bowtie is a meta-validator of the JSON Schema specification, by which we mean it coordinates executing other validator implementations, collecting and reporting on their results.
To do so it defines a simple input/output protocol (specified in this JSON Schema) which validator implementations can implement, and it provides a CLI which can execute supported implementations.
It's called Bowtie because it fans in lots of JSON then fans out lots of results: >·<. Looks like a bowtie, no? Also because it's elegant – we hope.
For more information, see Bowtie's documentation.