The following table lists acronyms used in this document, along with the chapter where they are first used or defined.
| Chapter | Acronym | Definition |
| 2 | ADR | Adiabatic Demagnetization Refrigerator |
| 7 | AE | Analog Electronics |
| 2 | BGO | Bismuth Germanate |
| 2 | BI | Back-illuminated |
| 3 | CALDB | Calibration Database |
| 6 | CAP | Calorimeter Analog Processor |
| 7 | CCD | Charge-Coupled Devices |
| 6 | CDP | Calorimeter Digital Processor |
| 3 | Co-I | Co-investigator |
| 7 | CTE | Charge Transfer Efficiency |
| 7 | CTI | Charge Transfer Inefficiency |
| 6 | CTS | Calorimeter Thermal Sink |
| 7 | CXB | Cosmic X-ray Background |
| 7 | DE | Digital Electronics |
| 6 | DMS | Dewar Main Shell |
| 6 | DSP | Digital Signal Processor |
| 2 | EEF | Encircled Energy Function |
| 5 | EOB | Extensible Optical Bench |
| 6 | FEA | Front End Assembly |
| 2 | FI | Front-illuminated |
| 6 | FW | Filter Wheel (on XRS) |
| 2 | FWHM | Full-width half-maximum |
| 3 | FITS | Flexible Image Transport System |
| 3 | FTOOLS | FITS Tools |
| Chapter | Acronym | Definition |
| 1 | GO | Guest Observer |
| 1 | GOF | Guest Observer Facility |
| 3 | GRB | Gamma-Ray Burst |
| 1 | GSFC | Goddard Space Flight Center |
| 2 | GSO | Gadolinium Silicate |
| 3 | HEASARC | High Energy Astrophysics Science Archive Research Center |
| 2 | HETG | High Energy Transmission Grating (on Chandra) |
| 2 | HPD | Half-Power Diameter |
| 1 | HXD | Hard X-Ray Detector |
| 1 | ISAS | Institute of Space and Astronautical Science |
| 6 | IVCS | Inner Vapor Cooled Shield |
| 1 | JAXA | Japan Aerospace Exploration Agency |
| 6 | JFET | Junction Field Effect Transistor |
| 2 | LETG | Low Energy Transmission Grating (on Chandra) |
| 7 | MPU | Main Processing Unit |
| 4 | NRA | NASA Research Announcement |
| 1 | NASA | National Aeronautics and Space Administration |
| 4 | NOI | Notice of Intent |
| 7 | NXB | Non-X-ray Background |
| 7 | OBF | Optical Blocking Filter |
| 2 | PIN | Positive Intrinsic Negative |
| 2 | PI | Principal Investigator |
| 7 | PPU | Pixel Processing Units |
| 4 | PSPC | Position-Sensitive Proportional Counter (on ROSAT) |
| 7 | P-Sum | Parallel-Sum |
| 7 | QDE | Quantum Detection Efficiency |
| 7 | RDD | Residual Dark-current Distribution |
| 2 | RGS | Reflection Grating Spectrometer (on XMM-Newton) |
| 4 | RFA | Research Focus Area |
| 3 | RPS | Remote Proposal Submission tool |
| 3 | SAA | South Atlantic Anomaly |
| 2 | S/C | Spacecraft |
| 6 | SIS | Solid-state Imaging Spectrometer (on ASCA) |
| 1 | SWG | Science Working Group |
| 7 | TCE | TEC Control Electronics |
| 7 | TEC | Thermo-Electric Coolers |
| 1 | TOO | Target Of Opportunity |
| 2 | USC | Uchinoura Space Center |
| 1 | XIS | X-Ray Imaging Spectrometer |
| 1 | XRS | X-Ray Spectrometer |
| 1 | XRT | X-Ray Telescope |
| 1 | XRT-I | X-Ray Telescope for one of the four XIS detectors |
| 1 | XRT-S | X-Ray Telescope for the XRS detector |