upside

noun

1. The highest or uppermost side or portion of something.
2. (figuratively)A favourable aspect of something that also has an unfavourable aspect.

   “The only upside of being over 35 is that you don't get raped as much.”

   “They said we’d be free of all that tedious European red tape and would take back control of our borders, encouraging anyone agitated by immigration to believe that fewer people would come in. There would be no downside, only upsides.”

3. An upward tendency, especially in a financial market etc.

prep

1. (informal)On the top of.

   “Ruth Ann clenched her hand around the hairbrush and felt like smacking Ashley upside the head with it. She knew better than to talk that way.”