part of anatomical structure organ Anatomical structure that performs a specific function or group of functions [WP]. CARO:0020004 EFO:0000634 EMAPA:35949 ENVO:01000162 FMA:67498 MA:0003001 OpenCyc:Mx4rv5XMb5wpEbGdrcN5Y29ycA OpenCyc:Mx4rwP3iWpwpEbGdrcN5Y29ycA Organs are commonly observed as visibly distinct structures, but may also exist as loosely associated clusters of cells that work together to perform a specific function or functions. UMLS:C0178784 WBbt:0003760 anatomical unit body organ element anatomical system