General Definition
The date on which a contract, agreement, or other legal document is to take effect
Incorporation Definition
The actual date a corporation or LLC has started its existance. Often this is the same as the "filing date", which is the date stamped on the filing documents (i.e. date the document was filed) by the state agency that handled the filing. The effective date can also be some specified date in the future. NOTE: The effective date may also obligate the entity to have to pay additional taxes or fees if said date is prior to a year end. Go to State Research for more info your state's annual filing requirements.