What is a Cocktail Dress?

If you will Google "black cocktail dress" chances are, results would include images of the searched item. Like this screen cap I got from Google:

Fashionabout.com defines Cocktail Attire as short, elegant dresses for her and dark suits for him. The little black dress is the ultimate cocktail dress and appropriate for most special occasions. 

However, Wikipedia has a contrary definition:

A cocktail dress or cocktail gown is a woman's dress worn at cocktail parties and semi-formal, or "black tie" occasions. The length of a cocktail dress is long, often touching the ankle. When it is about 5 cm (2 inches) above the ankle it is called tea length and when it is almost touching the ankle it is called ballerina length, although ballerina length dresses usually fall into the evening gown category.

These two confusing definitions made me lean more into believing the definition set by Fashionabout.com and so during one of the parties that I attended, I prepared a little black dress that I found online.

My dress is from Something Borrowed Collection carried by Zalora.