Refers to a difference or gap between levels, ranks, or stages. Often used in technical or formal contexts such as mathematics, statistics, or social analysis.
The income gap is widening.
Please calculate the difference of this data.
sequence of differences
Compound of 階 (kai, 'rank, level') and 差 (sa, 'difference'). The exact historical derivation is uncertain, but the term is used in modern technical and formal writing.