| Abbreviation | Semantic type | Relation count | Instance count |
| dsyn | Disease or Syndrome | 2603234 | 12591865 |
| aapp | Amino Acid, Peptide, or Protein | 4345793 | 11503829 |
| podg | Patient or Disabled Group | 199404 | 9258258 |
| bpoc | Body Part, Organ, or Organ Component | 1392967 | 8711584 |
| gngm | Gene or Genome | 3422406 | 6946503 |
| topp | Therapeutic or Preventive Procedure | 991912 | 5108457 |
| neop | Neoplastic Process | 802419 | 4650747 |
| cell | Cell | 807092 | 4346530 |
| mamm | Mammal | 456140 | 4230378 |
| phsu | Pharmacologic Substance | 1100842 | 4226225 |
| orch | Organic Chemical | 1550322 | 3485563 |
| bacs | Biologically Active Substance | 951043 | 2922549 |
| fndg | Finding | 592051 | 2906281 |
| patf | Pathologic Function | 667378 | 2828014 |
| popg | Population Group | 339502 | 2419899 |
| aggp | Age Group | 179259 | 2191630 |
| tisu | Tissue | 291668 | 1634166 |
| celc | Cell Component | 349980 | 1606480 |
| humn | Human | 94088 | 1537291 |
| sosy | Sign or Symptom | 275794 | 1400138 |
| diap | Diagnostic Procedure | 271705 | 1385473 |
| orgf | Organism Function | 292346 | 1307166 |
| inpo | Injury or Poisoning | 200300 | 1076107 |
| celf | Cell Function | 370243 | 1004738 |
| mobd | Mental or Behavioral Dysfunction | 186453 | 997544 |
| medd | Medical Device | 231139 | 976946 |
| blor | Body Location or Region | 121816 | 815859 |
| hlca | Health Care Activity | 131293 | 804177 |
| ortf | Organ or Tissue Function | 239274 | 783507 |
| bact | Bacterium | 206093 | 740072 |
| horm | Hormone | 196984 | 729328 |
| lbpr | Laboratory Procedure | 180191 | 695736 |
| virs | Virus | 129863 | 592618 |
| prog | Professional or Occupational Group | 159164 | 573583 |
| famg | Family Group | 103395 | 561050 |
| hops | Hazardous or Poisonous Substance | 228022 | 544493 |
| lipd | Lipid | 178580 | 530165 |
| inch | Inorganic Chemical | 205395 | 530002 |
| genf | Genetic Function | 160665 | 528710 |
| elii | Element, Ion, or Isotope | 158070 | 520328 |
| npop | Natural Phenomenon or Process | 128729 | 494258 |
| antb | Antibiotic | 143940 | 469268 |
| carb | Carbohydrate | 174876 | 444636 |
| plnt | Plant | 105405 | 414415 |
| anab | Anatomical Abnormality | 84672 | 392078 |
| resa | Research Activity | 30846 | 372320 |
| cgab | Congenital Abnormality | 103923 | 371013 |
| phsf | Physiologic Function | 107332 | 368390 |
| invt | Invertebrate | 76081 | 363812 |
| acab | Acquired Abnormality | 76161 | 351394 |
| imft | Immunologic Factor | 123209 | 346150 |
| moft | Molecular Function | 173023 | 329157 |
| anim | Animal | 62617 | 324249 |
| fngs | Fungus | 72852 | 298041 |
| comd | Cell or Molecular Dysfunction | 106122 | 286439 |
| inbe | Individual Behavior | 25904 | 279711 |
| bsoj | Body Space or Junction | 56163 | 279673 |
| nsba | Neuroreactive Substance or Biogenic Amine | 84244 | 271569 |
| emst | Embryonic Structure | 64781 | 265189 |
| ftcn | Functional Concept | 5110 | 250907 |
| orgm | Organism | 44452 | 230160 |
| strd | Steroid | 65144 | 214202 |
| hcro | Health Care Related Organization | 22721 | 178874 |
| nusq | Nucleotide Sequence | 59228 | 177531 |
| nnon | Nucleic Acid, Nucleoside, or Nucleotide | 74031 | 173703 |
| enzy | Enzyme | 51917 | 170942 |
| qnco | Quantitative Concept | 2698 | 152016 |
| fish | Fish | 36724 | 148001 |
| menp | Mental Process | 36551 | 144826 |
| eico | Eicosanoid | 48272 | 134468 |
| bdsu | Body Substance | 26715 | 125421 |
| orgt | Organization | 10696 | 120266 |
| inpr | Intellectual Product | 4548 | 116347 |
| orga | Organism Attribute | 32863 | 105949 |
| qlco | Qualitative Concept | 1735 | 104371 |
| biof | Biologic Function | 31772 | 100227 |
| chvs | Chemical Viewed Structurally | 43609 | 98439 |
| grup | Group | 19996 | 98190 |
| dora | Daily or Recreational Activity | 16213 | 93513 |
| resd | Research Device | 5501 | 91873 |
| tmco | Temporal Concept | 2088 | 89569 |
| irda | Indicator, Reagent, or Diagnostic Aid | 52257 | 87323 |
| amph | Amphibian | 12649 | 81813 |
| idcn | Idea or Concept | 3196 | 69411 |
| rcpt | Receptor | 26323 | 69093 |
| food | Food | 17574 | 63798 |
| emod | Experimental Model of Disease | 16886 | 63441 |
| chem | Chemical | 18593 | 59075 |
| spco | Spatial Concept | 1861 | 55146 |
| geoa | Geographic Area | 2859 | 52552 |
| opco | Organophosphorus Compound | 21406 | 49970 |
| bodm | Biomedical or Dental Material | 32554 | 49278 |
| chvf | Chemical Viewed Functionally | 15663 | 48482 |
| clas | Classification | 2768 | 45836 |
| bird | Bird | 9318 | 40544 |
| vtbt | Vertebrate | 6755 | 37554 |
| alga | Alga | 9949 | 35062 |
| clnd | Clinical Drug | 16182 | 34257 |
| rept | Reptile | 9892 | 33164 |
| edac | Educational Activity | 5207 | 32183 |
| bmod | Biomedical Occupation or Discipline | 10164 | 29746 |
| mnob | Manufactured Object | 2338 | 28805 |
| ocac | Occupational Activity | 4781 | 27678 |
| arch | Archaeon | 8093 | 27171 |
| sbst | Substance | 5481 | 26289 |
| mbrt | Molecular Biology Research Technique | 3913 | 24279 |
| rnlw | Regulation or Law | 2875 | 22972 |
| anst | Anatomical Structure | 4259 | 22777 |
| ocdi | Occupation or Discipline | 6384 | 21832 |
| rich | Rickettsia or Chlamydia | 5407 | 18639 |
| clna | Clinical Attribute | 4867 | 17740 |
| phpr | Phenomenon or Process | 3980 | 17689 |
| lbtr | Laboratory or Test Result | 6432 | 15702 |
| socb | Social Behavior | 1697 | 13360 |
| vita | Vitamin | 5589 | 11800 |
| gora | Governmental or Regulatory Activity | 2467 | 10483 |
| ffas | Fully Formed Anatomical Structure | 1386 | 6273 |
| bdsy | Body System | 2516 | 5396 |
| evnt | Event | 429 | 4840 |
| grpa | Group Attribute | 236 | 2948 |
| lang | Language | 210 | 2285 |
| mcha | Machine Activity | 1094 | 2272 |
| eehu | Environmental Effect of Humans | 229 | 1658 |
| shro | Self-help or Relief Organization | 444 | 1384 |
| amas | Amino Acid Sequence | 287 | 1021 |
| acty | Activity | 147 | 882 |
| pros | Professional Society | 291 | 679 |
| cnce | Conceptual Entity | 69 | 433 |
| bhvr | Behavior | 146 | 415 |
| hcpp | Human-caused Phenomenon or Process | 81 | 325 |
| mosq | Molecular Sequence | 119 | 190 |
| drdd | Drug Delivery Device | 86 | 121 |
| phob | Physical Object | 14 | 74 |