Get a single topic

It's easy to get a topic from the API with: /topics/<entity_id>. Here's an example:
That will return a Topic object, describing everything OpenAlex knows about the topic with that ID:
{
"id": "https://openalex.org/T11636",
"display_name": "Artificial Intelligence in Medicine",
// other fields removed for brevity
}
You can make up to 50 of these queries at once by requesting a list of entities and filtering on IDs using OR syntax.

Select fields

You can use select to limit the fields that are returned in a topic object. More details are here.