What are Verification and Validation in software world?

Verification is that the process of evaluating work-products (not the actual final product) of a development phase to determine whether they meet the specified requirements for that phase.

Activity of Verification: Reviews, Walkthroughs and Inspections

Question: Are we building the product right?

Validation is that the process of evaluating software during or at the end of the development process to determine whether it satisfies specified business requirements.

Activity of Validation: Testing

Question: Are we building the right product?

Ref: http://softwaretestingfundamentals.com/verification-vs-validation/