| Acronym | Meaning |
| WATOC | World Association Of Theoretically Oriented Chemists |
| WATOX | Western Atlantic Ocean Experiment |
| WATR | Water Attenuation By Transverse Relaxation |
| WAXD | Wide-angle X-ray Diffraction |
| WAXS | Wide-angle X-ray Scattering |
| WBC | White Blood Cell |
| WBEPM | Weakest Bound Electron Potential Model (theory In Calcns. Of Ionization Potentials) |
| WBG | Wide-band Gap |
| WBGT | Wet Bulb Global Temperature |
| WCA | Water Conservation Area(s) |
| WCA | Weeks-Chandler-Andersen (theory In Liq.-structure Calcns.) |
| WCAT | Water-cooled Atom Trap |
| WCBP | Well Characterized Biotechnology Pharmaceuticals |
| WCDF | Worse Case Dilution Factor (in Receiving Water) |
| WCOT | Wall Coated Open Tubular Columns |
| WCRP | World Climate Research Programme |
| WCUB | Wang Chang-Uhlenbeck-de Boer (quantum-mech. Relation In Rotational Relaxation Calcn.) |
| WDA | Weighted-density Approxn. (within D. Functional Formalism) |
| WDD | Weighted Density Distribution |
| WDF | Wigner Distribution Function (in Study Of Quantum Dynamics) |
| WDI | World Drug Index |
| WDM | Wavelength Division Multiplexing |
| WDS | Wavelength-dispersive Spectrometry |
| WDXRF | Wavelength Dispersive X-Ray Fluorescence |
| WECC | Western European Calibration Cooperation |
| WEDM | Wire Electric Discharge Machining |
| WEEE | Waste Electrical And Electronic Equipment |
| WEEL | Workplace Environmental Exposure Limits |
| WEF | Water Environment Federation (formerly WPCF) |
| WEFA | Window Evolving Factor Analysis |
| WEFT | Water Elimination By Fourier Transform |
| WELAC | Western European Laboratory Accreditation Cooperation |
| WENDB | Water Enforcement National Data Base |
| WEP | Weak Equivalence Principle |
| WERC | Waste-management Education & Research Consortium |
| WERL | Water Engineering Research Laboratory |
| WET | Waste Extraction Test |
| WET | Whole Effluent Toxicity |
| WFA | Window Factor Analysis |
| WFGD | Wet Flue Gas Desulfurization |
| WFI | Water For Injection (pharmaceutical Term) |
| WFM | Work Function Microscopy |
| WFPC2 | Wide Field Planetary Camera 2 |
| WFS | Work Function Spectroscopy |
| WGS | Water Gas Shift Reaction |
| WGSATM | Working Group On The Statistical Aspects Of Trend Monitoring (ICES) |
| WHAM | Windermere Humic Aq. Acid Model |
| WHH | Width At Half Height [in X-ray Diffraction] |
| WHIMS | Wet High Intensity Magnetic Separation |
| WHMIS | Workplace Hazardous Materials Information System (Canada) |