Naming convention for NIST elliptic curves in OPENSSL
The good thing about standards is that there are so many to choose from.

The P-192, P-224, P-256, P-384 and P-521 names come from the FIPS DSS (Latest version of which is FIPS 186-4):

https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.186-4.pdf

The secp224r1, secp384r1 and secp521r1 names come from SEC2:

https://www.secg.org/sec2-v2.pdf

The prime192v1 and prime256v1 names come from RFC3279:

https://www.ietf.org/rfc/rfc3279.txt

They're all the same curves though.