Initialism of science fiction or speculative fiction, often used to avoid having to choose between the two. / Initialism of square feet. / Initialism of spontaneous fission.

(pathology) A hernial protrusion of brain substance through an opening of the skull

(Now chiefly dialectal) The itch; any eruptive skin disorder. / (Now chiefly dialectal) Dandruff.

(pathology) A predisposition to gout or to arthritis.