means The act of confirming that something is true, accurate, or worthy — or the emotional reassurance that you, your feelings, or your choices are acceptable and recognized.

from From Latin 'validus,' meaning strong, robust, or effective — the same root that gives us 'valid' and 'valor.' It passed through Medieval Latin 'validare' (to make strong, to confirm) into English around the 17th century, first as a dry legal-logical term: to validate was to make a claim hold up. The modern psychological sense — needing your feelings seen and approved — is a much later softening of that hard Latin spine, turning 'made strong' into 'made to feel okay.'