Meanings

air layer

edgewise (e.g. load, compression)

drift (mining)

boundary layer

many a little makes a mickle

lower classes

housewife demographic

bottom layer

upper floor (of a high-rise building)

destitute poor class

medium and high-rise residential zone

low-rise residential zone

deep-seated landslide

target demographic

low-level clouds

stratoplane (hypothetical type of airplane)

mid-level clouds

geothermal reservoir

hardpan

iron pan