For the past few months I have noted that the "LTE" word on my iPhone has disappeared and is now replaced by just "4G". What does this mean for the average consumer? Is it the same thing with a different terminology?

LTE (Long Term Evolution) is the name used when the technology is approaching 4G. Since ITU-R set the 4G speed quite high and the current technology cannot yet meet, they use the term LTE. It was like before 3G they has 2.5G

So 4G is a step-up from LTE?

The 4G standard is set by international communication body ITU (or for radio section, ITU-R). Since no technology has yet to be able to meet the requirement of, the term currently used is LTE as technology progress to meet the "real" 4G. Right now I think not yet reach. So, many use term LTE but lately many want to show they are reaching the standard and use term like 4G LTE, just to make consumer think that they are going to be there first.