We don't have synonyms for semiform yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are aeriform, vermiform and reniform.
(n) :
(crystallography) A crystal structure that is more elaborate than the simplest (primitive) form but which does not include all the faces and symmetry elements characteristic of the full crystal system.
(n) :
(crystallography) A crystal structure that is more elaborate than the simplest (primitive) form but which does not include all the faces and symmetry elements characteristic of the full crystal system.