| animal stage | http://purl.obolibrary.org/obo/MAT_0000391 | animal stage | |
| anlage | http://purl.obolibrary.org/obo/MAT_0000478 | anlage | |
| antenna | http://purl.obolibrary.org/obo/MAT_0000086 | antenna | |
| anterior intestine | http://purl.obolibrary.org/obo/MAT_0000047 | small intestine | |
| anus | http://purl.obolibrary.org/obo/MAT_0000042 | anal region | |
| aorta | http://purl.obolibrary.org/obo/MAT_0000035 | aorta | |
| aortic arch | http://purl.obolibrary.org/obo/MAT_0000059 | branchial arch | |
| apical | http://purl.obolibrary.org/obo/MAT_0000484 | apical | |
| apoplasm | http://purl.obolibrary.org/obo/MAT_0000348 | apoplasm | |
| apoplast | http://purl.obolibrary.org/obo/MAT_0000348 | apoplasm | |
| appendage | http://purl.obolibrary.org/obo/MAT_0000023 | appendage | |
| appendix | http://purl.obolibrary.org/obo/MAT_0000287 | appendix | |
| archaeobacterium | http://purl.obolibrary.org/obo/MAT_0000193 | archaeobacterium | |
| artery | http://purl.obolibrary.org/obo/MAT_0000034 | artery | |
| arterial system | http://purl.obolibrary.org/obo/MAT_0000034 | artery | |
| ascending colon | http://purl.obolibrary.org/obo/MAT_0000311 | ascending colon | |
| atrioventricular node | http://purl.obolibrary.org/obo/MAT_0000498 | atrioventricular node | |
| atrium | http://purl.obolibrary.org/obo/MAT_0000496 | atrium | |
| auditory apparatus | http://purl.obolibrary.org/obo/MAT_0000138 | ear | |
| auditory system | http://purl.obolibrary.org/obo/MAT_0000138 | ear | |
| autopod | http://purl.obolibrary.org/obo/MAT_0000091 | autopod | |
| axial skeleton | http://purl.obolibrary.org/obo/MAT_0000148 | axial skeleton | |
| balancer organ | http://purl.obolibrary.org/obo/MAT_0000203 | haltere | |
| bark | http://purl.obolibrary.org/obo/MAT_0000360 | bark | |
| basal | http://purl.obolibrary.org/obo/MAT_0000485 | basal | |
| basal ganglion | http://purl.obolibrary.org/obo/MAT_0000450 | basal ganglion | |
| basal nucleus] | http://purl.obolibrary.org/obo/MAT_0000450 | basal ganglion | |
| basasl nucleus | http://purl.obolibrary.org/obo/MAT_0000200 | cranial ganglion | |
| biopsy | http://purl.obolibrary.org/obo/MAT_0000480 | biopsy | |
| bladder | http://purl.obolibrary.org/obo/MAT_0000122 | bladder | |