No, the "Wait" in this rule creates a subscription to the event, as @kyroha suspects above. The rule goes to sleep, then will wake when that event (sunrise, in this case) happens and continue with the next action. (So, for example, it does not mindlessly "spin" and constantly check whether the time is sunrise.)
This isn't a "Delay" per se (if we take that term to mean this specific Rule Machine action, which is called that), but delays work similarly: they create a scheduled job for whatever time in the future, then either wait for that (if using a standalone "Delay" action) or continue with the next action in the list (if using the "delay" option on a particular action).
This sounds like pre-Rule-4.0 rules (also part of what is now Legacy Rule Machine), so it must have really been a while. 
Rule truth is no longer a thing; everything can be done based on triggers and (in the actions) conditions, or new with Rule 5.0, predicate conditions (but I wouldn't rush to use them just because they're there). This post may be helpful for catching up on some of the history, including how to "translate" Rule 3.x logic:
