Third Overprint Accidental: philatelic term for a third overprint deviation caused by accidental
Shifted Third Overprint: postage stamp with caused by accidental shifted third overprint to another position as intended
Light Third Overprint: postage stamp with caused by accidental clear but too light third overprint
Strong Third Overprint: postage stamp with caused by accidental clear but too strong third overprint
Oily Third Overprint: postage stamp with caused by accidental too much oil in the third overprint colour which runs out