| AGR | Amitermes-Gnathamitermes-Rhynchotermes |
| AMD | acid mine drainage |
| ATP | adenosine triphosphate |
CCA | canonical correspondence analysis |
| CDC | Centers for Disease Control and Prevention |
| CDI | contact-dependent growth inhibition |
EHEC | enterohaemorrhagic Escherichia coli |
| EPS | extracellular polymeric substance |
FDH | formate dehydrogenase |
HA | hemagglutinin |
| HMP | Human Microbiome Project |
IBD | inflammatory bowel disease |
| IOM | Institute of Medicine |
LCA | last common ancestor |
MetaHIT | Metagenomics of the Human Intestinal Tract |
NA | neuraminidase |
| NASA | National Aeronautics and Space Administration |
| NEC | neonatal necrotizing entercolitis |
| NIH | National Institutes of Health |
| NMDS | nonmetric multidimensional scaling |
ORCA | Ocean Research and Conservation Association |
PCA | principal component analysis |
| PCR | polymerase chain reaction |
rRNA | ribosomal ribonucleic acid |