The term SCI-FI SUBJECT can be broken down into two crossword solutions: ALIEN (5 letters) and TIMETRAVEL (10 letters). Both of these terms are related to the genre of science fiction, which is a form of speculative fiction that often deals with imaginative and futuristic concepts such as advanced science and technology, space exploration, time travel, parallel universes, and extraterrestrial life. ALIEN refers to any creature or being from outer space, while TIMETRAVEL is the concept of traveling through time either forwards or backwards.