Trouble Understanding Key Rings and Key Ring Collections

Hello,

I am attempting to create an application that stores public and private PGP keys. I am using Java as the programming language.
My question is, what appears to be called a "Key Ring" is actually a Key, and a "Key Ring Collection" is the equivalent of a Key Ring in PGP, is that correct?
I am sorry if I have this all wrong. It appears that the following example code is used to create a key pair, though it is using a keyring as the Key, and KeyRingCollection to read the Keyring file.

https://github.com/bcgit/bc-java/blob/master/pg/src/main/java/org/bouncycastle/openpgp/examples/PGPExampleUtil.java


Is this because, a "key" is to be considered just the output of an algorithm, whereas a PGP Private Key, for example, contains multiple keys inside of it?

Thank you for your time.