This term refers to the amount of time, after the open time or flash time (if any), during which the adhesive you just applied will accept the flooring material and still provide an adequate bond. If you leave certain adhesives open to the atmosphere for too long, they will skin over or cure out and not be wet/sticky enough to accept the flooring material.  In other words, they will dry out. It is important to note that working time is often affected by the ambient temperature as well as the ambient humidity. For example, in arid conditions when the temperature is very high, working times will be much shorter for water-based materials but much longer for moisture-curing materials. Areas of high humidity and high temperature will have longer working times for water-based materials but potentially shorter working times for moisture-curing products. Cold temperatures are going to slow everything down whether the products be water-based or moisture-curing. For reactive adhesives like epoxies or epoxy-modified polyurethanes, temperatures will greatly affect the working time. Reactive adhesives are very sensitive to temperature, so cold conditions will extend the working time and hot conditions will speed things up.