All objects in the Kubernetes REST API are unambiguously identified by a Name and a UID.
For non-unique user-provided attributes, Kubernetes provides labels and annotations.
Names are generally client-provided. Only one object of a given kind can have a given name at a time (i.e., they are spatially unique). But if you delete an object, you can make a new object with the same name. Names are the used to refer to an object in a resource URL, such as /api/v1/pods/some-name. By convention, the names of Kubernetes resources should be up to maximum length of 253 characters and consist of lower case alphanumeric characters, -, and ., but certain resources have more specific restrictions. See the identifiers design doc for the precise syntax rules for names.
UID are generated by Kubernetes. Every object created over the whole lifetime of a Kubernetes cluster has a distinct UID (i.e., they are spatially and temporally unique).