Being an essential and permanent part of something.
Being an included feature that normally comes as an extra.
Constructed as a non-detachable part of a larger structure.
Anything (such as a piece of furniture, or a software feature) that is built in, not added as an extra.
Innate, inherent, inseparable from the thing itself, essential.
Built-in.
Situated, produced, secreted in, or coming from inside an organ, tissue, muscle or member.
A built-in function that is implemented directly by the compiler, without any intermediate call to a library.
An ability possessed by a character and not requiring any external equipment.