noun
bottom layer; lowest stratum
Refers to the physical or structural lowest layer of something, such as rock strata, paint layers, or organizational levels.
地層の最下層から化石が発見された。
Fossils were discovered in the bottom layer of the stratum.
この絵の具の最下層は青色だ。
The undermost layer of this paint is blue.
noun
lowest social class; bottom of society
Used for the lowest socioeconomic class or caste in a society. Often carries a negative or critical nuance.
彼は社会の最下層から身を起こした。
He rose from the lowest stratum of society.
その制度は最下層の人々をさらに苦しめた。
That system further afflicted people in the lowest class.
Means 'lower layer' or 'lower class', but not necessarily the very bottom.
Compound of 最 (sai, 'most') + 下 (ka, 'lower') + 層 (sō, 'layer/stratum').