Whats high functioning autism?

Hi everyone sorry if I have posted this in the wrong place. I'm just curious as to what is high functioning autism? I have been doing some research online as my daughter has been diagnosed as autistic (no mention of high functioning or aspegers as she is delayed everywhere) and we are now going down the path of getting a EHC as the mainstream school she is currently in isn't able to cope with her needs, even with a 1/1 teaching assistant at all times. As I have been doing some looking around online I keep noticing HFA and Aspergers and wondered if they are considered the same and what's the difference between that and ASD. Just wondered if someone could clarify this for me for future reference. I am fairly new to all this (dd was only diagnosed last December) so sorry if it seems silly. Just trying to understand all the different terminology 

thank you