AI	Artificial intelligence
Al	Aluminum
AGB	Accessory gear box
ANN	Artificial neural networks
ANOVA	Analysis of variance
CI	Confidence interval
d.f.	Degree of freedom
Fe	Iron
FH	Flight hour
FT-IR	Fourier transform infrared spectroscopy
IRQ	Interquartile range
ITWL	Air Force Institute of Technology in Warsaw
JOAP	Joint Oil Analysis Program
LSD	Least significant difference test
ODM	Oil debris monitoring
PCA	Principal component analysis
ppm	Parts per million (mg/kg)
RDE-AES	Rotating disc electrode atomic emission spectroscopy
Std	Standard deviation
SVM	Support vector machine
TBO	Time between overhaul
Zn	Zinc