Slash I think is used a little more in the fanfiction world. People write out the pairings in a story (say romance between Harry Potter and Ron Weasley) as Ron/Harry hence the slash term. For women, it would be Ginny/Hermione. So Harry SLASH Ron, or Hermione SLASH Ginny. Also known as femslash, femmeslash, yuri, shojo ai, you know the drill.