The phrase "loading period" refers to a specific period of time or process when something is being prepared or loaded, usually with things like data, information, or resources before it can be used or accessed. Full definition
For dogs under 20 lbs and under, you will give your dog one delicious soft chew after the 4 week loading period. (activphy.com)
For dogs 60 lbs and over, our 75 count will last you 2 and 1/2 months after the initial loading period. (activphy.com)
The nicely worked - out fighting system, the short loading periods and the ability to customize a gigantic load of character's made our day while playing this game. (metacritic.com)