The term 'structural opening' can be summarized as an INFRA, which is a five-letter word. An INFRA is a type of architectural feature that is used to provide an open space in a structure. It is usually found in the form of a window or door, and it can also be used to create a visual connection between two spaces. Infras are often used to create a sense of openness and lightness in a building, as well as to provide ventilation and natural light.