fan
n. Without qualification, indicates a fan of science
fiction, especially one who goes to cons and tends to hang out
with other fans. Many hackers are fans, so this term has been
imported from fannish slang; however, unlike much fannish slang it
is recognized by most non-fannish hackers. Among SF fans the
plural is correctly `fen', but this usage is not automatic to
hackers. "Laura reads the stuff occasionally but isn't really a
fan."