| ·AIP： | Aerodynamic Interface Plane |
| ·ARP： | Aerospace Recommended Practice |
| ·C： | Offset term (Equation A9) |
| ·C(τ)： | Covariance of time varying pressures |
| ·f： | Frequency |
| ·KC： | Circumferential distortion sensitivity (Equation A9) |
| ·KR： | Radial distortion sensitivity (Equation A9) |
| ·L： | Characteristic length (cowl lip to compressor face) |
| ·MPR： | Multiple-per-revolution element |
| ·N： | Number of instrumentation rings |
| ·P： | Total pressure |
| ·-
P： | Time-averaged total pressure |
| ·PAV： | Ring average total pressure |
| ·PAVLOW： | Average total pressure of low total-pressure region for a ring (Equations A2 and A5) |
| ·PFAV： | Face average total pressure (A.1.2) |
| ·PR： | Pressure ratio of given compression components |
| ·PRDS： | Stability pressure ratio with distortion |
| ·PRO： | Operating pressure ratio |
| ·PR1： | Undistorted stability pressure ratio |
| ·Q： | Number of low-pressure regions |
| ·R： | Radius |
| ·RMS： | Root mean square |
| ·SM： | Stability margin |
| ·T： | Total temperature |
| ·ΔPC/P： | Circumferential distortion intensity element (Equations A2 and A5, A.1.1) |
| ·ΔPR/P： | Radial distortion intensity element (Equation A8, A.1.2) |
| ·ΔPRMS： | Root mean square of time varying total-pressure fluctuations |
| ·ΔPRS： | Stability pressure ratio loss (Equation A9) |
| ·ΔSM： | Stability margin loss (Equation A10) |
| ·θ： | Circumferential location in degrees |
| ·θ
+： | Extent of high-total-pressure region |
| ·θ
–： | Extent of low-total-pressure region |
| ·τ： | Time increment |
| ·φ (f)： | Power spectral density of time-varying pressure |
| ·c： | Circumferential |
| ·i： | |
| ·j： | |
| ·k： | |
| ·MAX： | |
| ·MIN： | |
| ·r： | |