In mathematics, a<unk>  (or just<unk>  is a curve that can be formed by intersecting a cone (more precisely, a right circular<unk> al surface) with a plane. The<unk> s were named and studied as long ago as 200 BC, when Apollonius of Perga undertook a systematic study of their properties.
Conic section
ABCD rating
Frozen section procedure
Mastitis classification
Bleeding classification
Struma ovarii classification
Intussusception classification
Goiter classification