Class divisions in this society are gradually hardening.
Tips
usage
Outside the lab the figurative sense dominates: 阶层固化 (class divisions setting hard), 思维固化 (thinking that no longer moves). Both carry a complaint: something that ought to stay fluid has set.
memory
The 化 ending works like English -ize or -ify, 简化 to simplify, 恶化 to worsen, so 固 (firm) plus 化 reads as "firm-ify".
