The material used to form a weather-resistant seal around an operable sash is the weather-stripping.

Weep flaps are holes covered with vinyl to let water escape and keep bugs out.

Small openings on the exterior sill are weep holes. They are designed to allow water to escape that might otherwise accumulate in a window's sill.

Slots or holes in the sill (bottom) that allow water to run outside are weep slots.

Wet glazing uses a silicone-based substance to secure and seal glass to a sash.