Q. what is inception

According to the Encarta World English Dictionary inception is a formal word meaning the beginning of something.

Inception is also the title of a currently released movie directed by Christopher Nolan and starring Leonardo DiCaprio.  

In the movie an inception is a plot element that, if we were to post it here, would be a potential movie spoiler for other readers.  So, instead I'll direct you to the Wikipedia article regarding the movie.