The surname of the greatestcustomer name ever used in a software demo... "Bernard Owesome". The word has since come to signify anything that is an order of magnitude greater than just simply "awesome".
"Tommy Lee, go fuck yourself, how dare! There should be a special ring of hell for any man with the audacity to be bored of threesomes. I just want to slap him, 'Hey Tommy, why don't you try a couple of years of onesomes and then we'll talk chat on how boring threesomes are.'" -Christian Finnegan
For children, this is an adjective used to describe the child for making a good grade in school. On a report card, if they received an "O" for Outstanding, rather than an "A", they are described as 'owesome'.
As a more mature word, this adjective is used to describe something so awesome, it makes you want to "oh!" (orgasm).
"Wow, Johnny got an 'A' for 'awesome', and his little sister got an 'O' for.... 'owesome'."