Origin:  The word HEMI originated from the Greek word HEMISUS which means Half.  
The words derived from this possess the above meaning.  
Words:  
Hemisphere = Half of the sphere 
Hemicycle = A curved or semicircular structure or arrangement 
Hemiplegia = Paralysis of one side of the body  
Hemiballismus = It is a very rare movement disorder 
Hemicryptophyte = A perennial plant having its overwintering buds located at the soil surface.  
Hemicube = An abstract regular polyhedron containing half the faces of a cube 
Hemipolyhedron = It is a uniform star polyhedron some of whose faces pass through its center 
Hemitonic = Relating to half steps; one or more semitones