Mariners are familiar with ETA - Estimated Time of Arrival. (Not exact time of arrival as I once head a tug captain loudly explain to his boss.)
When an upgrade to the weather routing software was sent out a couple years ago it had a space for RTA - Requested Time of Arrival which I had never seen before but have found it useful
In general ETA is arrival time at a given speed, RTA is when the arrival time is given and the required speed is calculated.
etc. - “Best ETA” and “Fresh ETA”
“Best ETA” is a little vague but I take it to mean ETA using the most optimistic assumptions, no weather or other delays, best speed.
“Fresh ETA” which I like, sort of a “knock off the bs”, there is a tendency, once an initial ETA is sent, to adjust it rather than accept it’s no longer useful. For example if the ETA looks like its off by 4 hours it might seem better to adjust it 2 hours one day and 2 hours the next. With a “fresh ETA” just forget the old ETA and work up a new one.