Definition - What does Weep mean?
A weep is a small opening that allows water to drain from within an assembly. The term is usually applied to a tiny leak in a boiler joint which forms droplets (or tears) of water very slowly. Weeps can cause corrosion in boilers and heat exchangers.
In building construction, weeps are typically found in masonry cavity walls, just above the flashing. Weeps are necessary in a retaining wall, so water can escape from the retained earth, thus lessening the hydrostatic load on the wall and preventing moisture damage from freeze/thaw cycles.
A weep is also known as a weep hole, weeper or weep-brick.
Corrosionpedia explains Weep
Weeps are used to drain off accumulated moisture, as from condensation or seepage. For example, there are weeps in many spots throughout the gasket on heat exchanger plates that cause the fluid to spill to the ground rather than going unnoticed inside the unit. These weeps are in locations that do not see any flow unless a problem occurs.
Weeps are located at the bottom of the object to allow for drainage; the weep hole must be sized adequately to overcome surface tension. Typically, weeps are arranged to direct water which may have entered an assembly from outside back to the outside. Weeps may also be found in metal windows and glazed curtain walls to permit internal condensation to escape.
During the hydrostatic test inspection of the boiler, a few weeps may be observed. If the weeping tubes are just a few in number and the leak is just a drop or two every few minutes, this is not of great concern. Chances are very good the weeps will dry up completely when the boiler is fired. If, however, there are tubes leaking at a rate of more than one or two drops every few minutes, then the leaking tubes should be re-rolled.