Mark off Definition 1 of 3Pro Tip 1/3Physical Spaces Used when physically separating spaces, often in construction or decoration. The architect marked off the zones for each department. Pro Tip 2/3Planning Stages Useful during planning, to visually break down areas before starting a project. We should mark off the sections of the garden first. Pro Tip 3/3Visual Aid It can help create a visual guide for limits or allocations in shared spaces. Let's mark off each vendor's space at the market.