[moandcompany]

Yep... Along with this

Verification aligns with a specification. E.g. verify if what was implemented matches what was specified.

Validation aligns with a requirement. E.g. verify if what was implemented solves the actual problem.

[tirant]

I like to talk about goals and not requirements.

What is your product goal? Both for the customer (solving a problem) and for the company(solve a marketing need, make money)?

Can you proof that you are meeting both? Then you are validating your goals successfully.

Most of the time products are missing defined goals, so lots of people have no idea what the fuck they are developing and everyone ends up with their own idea of the product.

[friendzis]

Engineering specifications implement requirements.

EDIT: more formally, specification is a document stating requirements

[ijustlovemath]

Usually there's a separate document that has the requirements, and from that document you have a "software detailed design" which has the specifications for how to build the software such that it upholds the requirements. Subtle but important difference.