ME D ▁CT ▁( System at ized ▁N omen cl ature ▁of ▁Medicine — C lin ical ▁Term s ) ▁ ▁S ugg ested ▁Upper ▁Mer ged ▁Ont ology , ▁a ▁formal ▁upper ▁ont ology ▁ ▁Systems ▁Bi ology ▁Ont ology ▁( SB O ), ▁for ▁computational ▁models ▁in ▁bi ology ▁ ▁S WE ET , ▁Sem antic ▁Web ▁for ▁Earth ▁and ▁Environment al ▁Term in ology ▁ ▁Th ought T re asure ▁ont ology ▁ ▁T IME - ITE M , ▁Top ics ▁for ▁Index ing ▁Medical ▁Education ▁ ▁U ber on , ▁representing ▁animal ▁an atom ical ▁structures ▁ ▁U MB EL , ▁a ▁light weight ▁reference ▁structure ▁of ▁ 2 0 , 0 0 0 ▁subject ▁concept ▁classes ▁and ▁their ▁relationships ▁derived ▁from ▁Open C yc ▁ ▁Word Net , ▁a ▁lex ical ▁reference ▁system ▁ ▁Y AM AT O , ▁Yet ▁Another ▁More ▁Advanced ▁Top - level ▁Ont ology ▁ ▁The ▁W 3 C ▁Link ing ▁Open ▁Data ▁community ▁project ▁coordinates ▁attempts ▁to ▁conver ge ▁different ▁ont ologies ▁into ▁world wide ▁Sem antic ▁Web . ▁ ▁L ibr aries ▁ ▁The ▁development ▁of ▁ont ologies ▁has ▁led ▁to ▁the ▁emer gence ▁of ▁services ▁providing ▁lists ▁or ▁directories ▁of ▁ont ologies ▁called ▁ont ology ▁libraries . ▁ ▁The ▁following ▁are ▁libraries ▁of ▁human - selected ▁ont ologies . ▁ ▁CO LO RE ▁is ▁an ▁open ▁repository ▁of ▁first - order ▁ont ologies ▁in ▁Common ▁Log ic ▁with ▁formal ▁links ▁between ▁ont ologies ▁in ▁the ▁repository . ▁ ▁DA ML ▁Ont