What does the term 'viscosity' mean?
Viscosity is the measure of a fluid's resistance to flow. The higher the viscosity of a liquid, the thicker it is and the greater the resistance to flow.
Glue can be various measures of viscosity, with each measure having it's own benefits based on the application required. Low viscosity glue will spread easily, whereas high viscosity glue is ideal for vertical surfaces or areas that need a concentrated application.