router
Software that automatically sends each request to the right one of several trained models.
Some systems have more than one trained model, say one tuned for English and one for other languages. A router looks at each incoming request. It decides which model should handle it, without a person choosing by hand.
Think of it as
Like a receptionist who directs each visitor to the right department based on what they need, without the visitor having to know the building's layout.
Example
A support tool receives a ticket written in Spanish. The router notices the language and sends it to the multilingual model, while English tickets go to the faster English-only model. Nobody on the team has to choose.