A measurement or measurement of distance expressed in feet; the total number of feet in a length or area.
From 'feet' (plural of foot, Old English 'fōt') + '-age' (suffix forming nouns of quantity or collection). This follows patterns like 'footage' and 'yardage'.
Though feetage' exists, English speakers almost always use 'footage' instead—it's a perfect example of how one variant completely dominates over another, making the alternative seem awkward.
Complete word intelligence in one call. Free tier — 50 lookups/day.