overmargin noun 2verb 1forms 3 noun2 •The amount by which something is bigger, stronger, or with greater capacity than the absolute minimum.Breastbeams—wood, cast steel, angles and channels—are carefully designed, with a big overmargin of strength. — 1914 •The upper rim or border of something. verb1 •To invest too much on margin, increasing risk and limiting operating capital.Algorithms in current use differ in their ability to select a matching that does not overmargin a complicated position. — 1984 formsovermargined · overmargining · overmargins