| Term | Definition / Meaning / Stand for |
| W Virginis |
A type of Type II Cepheid variable star used as a standard candle in distance measurements. |
| WZ Sagittae |
A type of dwarf nova characterized by rare but very large outbursts. |
| W Ursae Majoris |
A type of eclipsing binary star system where the two stars share a common envelope and are in contact with each other. |
| WCDM |
Warm Cold Dark Matter |
| WMC |
Warm Molecular Cloud |
| WNAR |
Warm Neutral Atomic Region |
| WNM |
Warm Neutral Medium; a component of the interstellar medium consisting of warm, neutral hydrogen gas. |
| WORM |
Warm Outer Region Model |
| WVC |
Warm Vibrational Cloud |
| WHIM |
Warm-Hot Intergalactic Medium |
| WFS |
Wavefront Sensor |
| WHL |
Weak Lensing Halo |
| WL |
Weak Lensing |
| WMG |
Weak Magnetic Galaxy |
| WMS |
Weak Magnetic Star |
| WNS |
Weak Neutron Star |
| WP |
Weak Photon Interaction |
| WRI |
Weak Radio Interferometer |
| WSR |
Weak Solar Radiation |
| WS |
Weak Spectrum |
| WSM |
Weak Stellar Magnetic Field |
| WTA |
Weak Transit Atmosphere |
| WTG |
Weak Turbulence Galaxy |
| WV |
Weak Variability |
| WW |
Weak Wind |
| WXG |
Weak X-ray Galaxy |
| WXR |
Weak X-ray Region |
| WXS |
Weak X-ray Source |
| WXV |
Weak X-ray Variability |
| WZA |
Weak Zonal Anisotropy |
| WZG |
Weak Zonal Gradient |
| WZM |
Weak Zonal Motion |
| WZV |
Weak Zonal Variability |
| WTTS |
Weak-lined T Tauri Star |
| WIMP |
Weakly Interacting Massive Particle; a hypothetical particle that is a candidate for dark matter. |
| WMP |
Weakly Magnetized Plasma |
| WRC |
Weakly Rotating Core |
| WSF |
Weakly Star-Forming |
| WTP |
Weakly Thermal Plasma |
| WYB |
Weakly Young Binary |
| WYG |
Weakly Young Galaxy |
| WYL |
Weakly Young Luminosity |
| WYM |
Weakly Young Magnetar |
| WYR |
Weakly Young Region |
| WYV |
Weakly Young Variable Star |
| WZD |
Weakly Zoned Disk |
| WZG |
Weakly Zoned Galaxy |
| WZT |
Weakly Zoned Telescope |
| WENSS |
Westerbork Northern Sky Survey; a radio survey of the northern sky conducted with the Westerbork Synthesis Radio Telescope. |
| WRST |
Westerbork Synthesis Radio Telescope; a radio telescope in the Netherlands used for astronomical observations. |
| WSRT |
Westerbork Synthesis Radio Telescope; another abbreviation for the same telescope mentioned above. |
| WINER |
Western Institute for Near Earth Research |
| WB |
White Dwarf Binary |
| WD |
White Dwarf |
| WET |
Whole Earth Telescope; an international collaboration of observatories that coordinate to provide continuous observations of variable stars. |
| WAC |
Wide Angle Camera |
| WAM |
Wide Angle Magnetometer |
| WASP-XX |
Wide Angle Search for Planets (Exoplanet System) |
| WASP |
Wide Angle Search for Planets; a project aimed at detecting exoplanets using wide-field photometry. |
| WAP |
Wide Aperture Photometer |
| WFCP |
Wide Field Camera Photometer |
| WFC |
Wide Field Camera; an instrument on the Hubble Space Telescope used for capturing wide-field images. |
| WFC |
Wide Field Camera |
| WFIRST |
Wide Field Infrared Survey Telescope; a planned NASA observatory designed to perform wide-field imaging and surveys in the infrared spectrum. |
| WFM |
Wide Field Monitor |
| WFPC2 |
Wide Field Planetary Camera 2 (Hubble Space Telescope Instrument) |
| WFT |
Wide Field Telescope |
| WFPC |
Wide Field and Planetary Camera; an earlier camera on the Hubble Space Telescope that provided wide-field and high-resolution imaging. |
| WRO |
Wide Range Observatory |
| WSP |
Wide Stellar Population |