| 1D | one-dimensional |
| 2D | two-dimensional |
| 3D | three-dimensional |
| AAS | American Astronomical Society |
| AGU | American Geophysical Union |
| ALMA | Atacama Large Millimeter/Submillimeter Array |
| AO | adaptive optics |
| APLC | apodized pupil Lyot coronagraph |
| ARIEL | Atmospheric Remote-Sensing Infrared Exoplanet Large-Survey |
| AU | astronomical unit |
| CARMENES | Calar Alto High-Resolution Search for M Dwarfs with Exoearths with Near-Infrared and Optical Échelle Spectrographs |
| CASE | Contribution to ARIEL Spectroscopy of Exoplanets |
| CCD | charge coupled device |
| CFAO | Center for Adaptive Optics |
| CHEOPS | Characterising Exoplanet Satellite |
| CoRoT | Convection, Rotation, and Planetary Transits |
| COS | Cosmic Origins Spectrograph |
| CUTE | Colorado Ultraviolet Transit Experiment |
| DOD | Department of Defense |
| DST | Decadal Survey Testbed |
| ELT | Extremely Large Telescope |
| EMCCD | electron multiplying charge coupled device |
| EOS | equations of state |
| EPRV | extremely precise radial velocity |
| ERS | Early Release Science |
| ERS | European remote sensing satellite |
| ESA | European Space Agency |
| ESPRESSO | Échelle Spectrograph for Rocky Exoplanet- and Stable Spectroscopic Observations |
| EUV | extreme ultraviolet |
| ExAO | extreme adaptive optics |
| ExEP | Exoplanet Exploration Program |
| Exo-C | Exoplanet Direct Imaging: Coronagraph |
| Exo-S | Exoplanet Direct Imaging: Starshade |
| ExoPAG | Exoplanet Exploration Program Analysis Group |
| FFP | free-floating planet |
| FGS | fine guidance sensor |
| FIES | Fiber-Fed Échelle Spectrograph |
| FIR | far infrared |
| FOV | field of view |
| FUV | far ultraviolet |
| GALEX | Galaxy Evolution Explorer |
| G-CLEF | Giant Magellan Telescope-Consortium Large Earth Finder |
| GCM | general circulation model |
| GMT | Giant Magellan Telescope |
| GMTNIRS | Giant Magellan Telescope Near-Infrared Spectrograph |
| GPI | Gemini Planet Imager |
| GSMT | giant segmented mirror telescope |
| Gyr | billion years |
| HabEx | Habitable Exoplanet Imaging Mission |
| HARPS | High Accuracy Radial Velocity Planet Searcher |
| HARPS-N | High Accuracy Radial Velocity Planet Searcher-North |
| HD | hydrogen deuteride |
| HDS | high-dispersion spectroscopy |
| HIRIS | High Resolution Imaging Spectrometer |
| HITRAN | high-resolution transmission |
| HOSTS | Hunt for Observable Signatures of Terrestrial Systems |
| HROS | High-Resolution Optical Spectrometer |
| HST | Hubble Space Telescope |
| HZ | habitable zone |
| IFS | Integral Field Spectrograph |
| IFU | Integral Field Unit |
| IR | infrared |
| IR-APD | infrared avalanche photodiodes |
| IRDIS | Infra-Red Dual-Beam Imager and Spectrograph |
| IWA | inner working angle |
| JPL | Jet Propulsion Laboratory |
| JWST | James Webb Space Telescope |
| KELT-FUN | Kilodegree Extremely Little Telescope Follow-Up Network |
| KGMT-FUN | Korean Giant Magellan Telescope Follow-Up Network |
| KMTNet | Korean Microlensing Telescope Network |
| L2 | Lagrange 2 point |
| LBT | Large Binocular Telescope |
| LBTI | Large Binocular Telescope Interferometer |
| LCOGT | Las Cumbres Observatory Global Telescope |
| LRS | Low Resolution Spectrometer |
| LSST | Large Synoptic Survey Telescope |
| LTE | local thermodynamic equilibrium |
| LUVOIR | Large UV/Optical/IR Surveyor |
| ME | mass—Earth |
| MJ | mass—Jupiter |
| MP | mass—planet |
| METIS | Mid-Infrared E-ELT Imager and Spectrograph |
| MHD | magnetohydrodynamics |
| MIR | mid-infrared |
| MIRI | Mid-Infrared Instrument |
| MKID | microwave kinetic inductance detector |
| MOA | Microlensing Observations in Astrophysics |
| MRI | magnetorotational instability |
| MRS | Medium Resolution Spectroscopy |
| MS | main sequence |
| Myr | million years |
| NAI | NASA Astrobiology Institute |
| NASA | National Aeronautics and Space Administration |
| NExSS | Nexus for Exoplanet Systems Science |
| ngVLA | Next Generation Very Large Array |
| NICMOS | Near Infrared Camera and Multi-Object Spectrometer |
| NIR | near infrared |
| NIRES | Near-Infrared Échelle Spectrometer |
| NN-EXPLORE | NASA-NSF Exoplanet Observational Research |
| NOAO | National Optical Astronomy Observatory |
| NSF | National Science Foundation |
| NUV | near ultraviolet |
| OGLE | Optical Gravitational Lensing Experiment |
| OST | Origins Space Telescope |
| OWA | Outer Working Angle |
| PI | principal investigator |
| PLATO | Planetary Transits and Oscillations of Stars |
| PM | phase modulation |
| PRIME | Prime focus Infrared Microlensing Experiment |
| PSF | point spread function |
| QE | quantum efficiency |
| R* | radius—star |
| Re | radius—Earth |
| Rp | radius—planet |
| R&D | research and development |
| RMS | root-mean-square |
| RT | radiative transfer |
| RV | radial velocity |
| SAG | Study Analysis Group |
| SCDA | Segmented Coronagraph Design and Analysis |
| SDT | science definition team |
| SED | spectral energy distribution |
| SHW2018 | Sexual Harassment of Women (National Academies 2018 report) |
| SIM | Space Interferometry Mission |
| SNR | signal-to-noise ratio |
| SPARCS | Star-Planet Activity Research CubeSat |
| SPECULOOS | Search for Habitable Planets Eclipsing Ultra-Cool Stars |
| SPHERE | Spectro-Polarimetric High-Contrast Exoplanet Research |
| SSB | Space Studies Board |
| STDT | Science and Technology Definition Team |
| STEM | science, technology, engineering, and mathematics |
| STIS | Space Telescope Imaging Spectrograph |
| STScI | Space Telescope Science Institute |
| TDEM | Technology Demonstration for Exoplanet Missions |
| TESS | Transiting Exoplanet Survey Satellite |
| TMT | Thirty Meter Telescope |
| TPF-C | Terrestrial Planet Finder Coronagraph |
| TPF-I | Terrestrial Planet Finder Interferometer |
| TRAPPIST | Transiting Planets and Planetesimals Small Telescope |
| TRL | technology readiness level |
| TTV | transit timing variation |
| URM | underrepresented minority group |
| vc | vortex coronagraph |
| Vis | visible |
| VLT | Very Large Telescope |
| VLTI | Very Large Telescope Interferometer |
| WISE | Wide-field Infrared Survey Explorer |
| WFIRST | Wide-Field Infrared Survey Telescope |
| WFIRST-CGI | Wide-Field Infrared Survey Telescope-Coronagraph Instrument |
| WIETR | WFIRST Independent External Technical/Management/Cost Review |
| XRP | Exoplanets Research Programs |
| XUV | extreme ultraviolet |