“Compliance” to a standard is weaker than “validation” or “certification” against a standard. Compliance indicates that a vendor recognizes a particular standard and has chosen to make design decisions that encompass most, if not all, of the standard.
When a vendor has implemented all of the required standard, that vendor will frequently upgrade their statement to “completely compliant” or “guaranteed compliant.”
A common example of compliance in the file transfer industry is a claim to “SFTP interoperability.” Today, there is no universally-recognized third-party laboratory that will test, validate and stand behind these claims, but there are hundreds of vendors who claim that their products are compliant with various known SFTP standards, such as compatibility w/ OpenSSH and/or fidelity to RFC 4250.
Another common example of compliance in the file transfer industry is “FIPS compliance“. This slippery phrase often indicates that the cryptography used a particular solution implements some or all the algorithms specified in FIPS 140-2 (e.g., AES) but that the underlying cryptography component has not been validated by a third party.