High Quality Content by WIKIPEDIA articles! Hatch marks are frequently used as an alternate form of abbreviation for some common units of measurement. In regard to distance, a single hatch mark typically indicates feet and a double hash mark indicates inches within the English system. In regard to time, a single hatch mark indicates minutes and a double hatch mark indicates seconds; these typically occur following hours, indicated by an elevated circle. The same system is used within Geometry and Trigonometry for the measurement of angles in degrees, minutes and seconds.