1. Every part of a place or surface. On New Year's Eve, I want every inch of this room covered in confetti when the clock hits midnight. Every inch of her face was covered in make-up, and, unfortunately, it showed.

2. Fully embodying a certain role, trait, or look. Always precedes a noun phrase. The designer will understand if you want to make more changes—he is every inch the professional. Wow, your costume is great! You look every inch the old Hollywood starlet.