▁not ▁be ▁limited ▁to ▁these ▁forms . ▁Ont ologies ▁are ▁also ▁not ▁limited ▁to ▁conserv ative ▁definitions   — ▁that ▁is , ▁definitions ▁in ▁the ▁traditional ▁logic ▁sense ▁that ▁only ▁introduce ▁termin ology ▁and ▁do ▁not ▁add ▁any ▁knowledge ▁about ▁the ▁world . ▁To ▁specify ▁a ▁concept ual ization , ▁one ▁needs ▁to ▁state ▁ax i oms ▁that ▁do ▁const rain ▁the ▁possible ▁interpret ations ▁for ▁the ▁defined ▁terms . ▁ ▁As ▁ref in ement ▁of ▁Gr uber ' s ▁definition ▁Fe il may r ▁and ▁W öß ▁( 2 0 1 6 ) ▁stated : ▁" An ▁ont ology ▁is ▁a ▁formal , ▁explicit ▁specification ▁of ▁a ▁shared ▁concept ual ization ▁that ▁is ▁character ized ▁by ▁high ▁semantic ▁express iveness ▁required ▁for ▁increased ▁complexity ." ▁ ▁Com ponents ▁▁ ▁Contempor ary ▁ont ologies ▁share ▁many ▁struct ural ▁similar ities , ▁regardless ▁of ▁the ▁language ▁in ▁which ▁they ▁are ▁expressed . ▁ ▁Most ▁ont ologies ▁describe ▁individuals ▁( inst ances ), ▁classes ▁( con cept s ), ▁attributes ▁and ▁relations . ▁ ▁In ▁this ▁section ▁each ▁of ▁these ▁components ▁is ▁discussed ▁in ▁turn . ▁ ▁Common ▁components ▁of ▁ont ologies ▁include : ▁ ▁Ind ividual s ▁ ▁Inst ances ▁or ▁objects ▁( the ▁basic ▁or ▁" ground ▁level " ▁objects ) ▁ ▁Class es ▁ ▁S ets , ▁collections , ▁concepts , ▁classes ▁in ▁programming , ▁types ▁of ▁objects ▁or ▁kinds ▁of ▁things ▁ ▁Att ributes ▁ ▁As pect s , ▁properties , ▁features , ▁characteristics ▁or ▁parameters ▁that ▁objects ▁( and ▁classes