What is falsetto?

Is it like head voice but airy and weak? I can’t hit high notes but I’m very strong and confident in chest voice and when I try sing the higher notes I physically can’t without switching into this airy like whispery singing which u can obviously still hear but it’s just not strong and what is head voice and how do I do that? and is falsetto ur potential/what you could achieve? Sorry for loads of questions im just so confused.