Seal is a verb that refers to closing or isolating something, but in Brazil it is popularly used as a slang, which serves as synonymous with "destroying", "running well" or "successful".
As slang, the term “seal” is used as a compliment, a way of congratulating someone for being successful at something.
Example:"Today we will seal the track" – phrase that conveys the idea of “today we are going to be successful on the dance floor”.
It is also common to use the slang "seal" to refer to the victory that a certain person obtained over his "enemies".
Example:"She sealed the enemies", a phrase that means “she was successful over her enemies”.
The “seal” appeared on the internet as a meme, thanks to the video published by youtuber Brazilian Romagaga, in 2013. The term “sealing” has been widely adopted by the homosexual community.
Learn more about meaning of memes.
Officially in the Portuguese language, to seal means to “seal”, “isolate” or “close” an opening.
Example: "He sealed the windows to protect himself from the storm".
See also: the meaning of sealed.