noun, noun which may take the genitive case particle 'no'
lower layer; layer beneath
Physical or structural lower layer, such as in geology, soil, atmosphere, or layered objects.
Fossils were found in the lower layer of the stratum.
noun, noun which may take the genitive case particle 'no'
lower strata; lower classes
Social or economic lower classes; often used in sociological or political contexts.
Heavier particles sink down to the lower layer.
ケーキの下層はスポンジで、上層はクリームだ。
The lower layer of the cake is sponge, and the upper layer is cream.
The policy had a major impact on the lower strata of society.
He grew up in the lower strata of society.
In this soil, clay forms the lower layer.
That family belonged economically to the lower class.
下流 can refer to a lower social class much like 下層, but it more literally means downstream and carries an older, more literary flavor.
下層 means the lower stratum or lower class of society, similar to 底辺 but generally less harsh or stigmatizing.
上層 is the upper layer or upper class, the direct opposite of 下層 in both the physical and social senses.
Compound of 下 (lower) and 層 (layer, stratum).