hereat vs later

hereat

• At this time; upon this event. 

• At this; because of this. 

later

• At some unspecified time in the future. 

• Afterward in time (used with than when comparing with another time). 

• At some time in the future. 

• Coming afterward in distance (following an antecedent distance as embedded within an adverbial phrase) 

• Coming afterward in time (used with than when comparing with another time). 

• See you later; goodbye.