That is a "cave."
A dungeon with an opening at the top is called a skylight dungeon. These types of dungeons allow natural light and ventilation to enter the space from above.
The opening at the edge of a forest is called a clearing. It is an area where there are few or no trees or vegetation, allowing more sunlight to reach the ground. Clearings can be natural or created by human activity.
They are called "jack studs" above the opening and "king studs" below the opening. These studs help support the header above the opening in a framed wall structure.
The opening at the top of a volcano is called a crater. It is where volcanic eruptions typically occur.
The opening of a letter is called a salutation. It typically includes a greeting, such as "Dear [Name]," followed by a comma.
A dungeon with an opening at the top is called a skylight dungeon. These types of dungeons allow natural light and ventilation to enter the space from above.
An orifice is a natural opening.
The opening at the edge of a forest is called a clearing. It is an area where there are few or no trees or vegetation, allowing more sunlight to reach the ground. Clearings can be natural or created by human activity.
An artificial opening is an opening in the body that has been created by a health care provider. It is not a natural opening. For example, in rare serious emegency sutuations, a paramedic or a physician may have to create an artificial opening in the neck so that the patient can breathe. This is called a tracheostomy. By law, only paramedics and physicians can perform this procedure.
The opening of a volcano is called the vent.The opening of a volcano is called a vent.
It is called the hatchway. If it is a round opening, it is called a scuttle. If it is a square opening it is called a hatch. Depending on the vessel and the location they can be "dogged" open.
The opening is called a stomata, which is regulated by two guard cells.
A natural opening where water can return to the surface is called a spring. Springs occur when groundwater flows up to the surface through an opening in the Earth's crust, such as a crack or fissure, due to pressure differences or geological formations. This allows the water to emerge on the land surface or into a body of water.
A natural opening through which water trapped underground can return to the surface is called a spring. Springs occur when water from an aquifer flows to the surface due to the pressure from the saturated rock layers. They can be a vital source of freshwater in many ecosystems.
The opening of a volcano is called the caldera.
The entrance to a cavity is called an "orifice." It is the opening that allows access to the internal space of the cavity, whether it be natural, like a mouth or nostril, or artificial, such as an opening in a structure or a drilled hole. In anatomical contexts, it often refers to openings in the body that lead to internal organs or spaces.
It is called the crater