mean potential water powermean quadratic errormean rangemean refractive indexmean sea level or msl or mslmean sieve sizemean speedmean spot speedmean square errormean squared errormean tide level or mtl or mtl or mean sea levelmean velocitymean water levelmeandermeander beltmeander cusp or terrace cusp or terrace cuspmeander lengthmeander nichemeander scarmeander widthmeanderingmearspid periodmeasured coal resourcesmeasured oremeasurementmeasuring chainmeasuring cylindermeasuring flumemechanical aerationmechanical analysismechanical anchoragemechanical bondmechanical classifiermechanical claymechanical efficiencymechanical erosion or corrasion or corrasionmechanical restraintmechanical stabilizationmechanical twinmechanical weatheringmechanismmechanism of mixingmechanoglyphmechcnical claymecopteramedaitemedenbachitemediamedial or middle or middlemedian diameter