"Outercourse" is a term that's sometimes used to describe sex that doesn't involve intercourse. That can include "dry sex" and/or many other sexual activities.
But like many other terms, different people define it in different ways.
Generally, intercourse is a high-risk activity for both pregnancy and transmission of STDs/STIs, and non-intercourse activities are typically lower-risk. But that doesn't mean they are "no risk".
Check out What's The Risk? - Five Easy Pregnancy Risk Assessment Flow Charts and A Quickie STD/STI Risk Assessment for info on the risks of different sexual activities.
"Sex" can include a lot of different sexual activities, all of which seem pretty "real" to me . It doesn't just mean intercourse, so "outercourse" isn't an "alternative to sex" - it is a form of sex.
(Why not take a look at http://www.scarleteen.com/sexuality/advice.html for one answer to the question "What IS sex, anyway?").