An aspect, phase, or condition — a particular facet or appearance of something.
事件は新たな様相を見せ始めた。
The case began to show a new aspect.
経済の様相が大きく変わってきている。
The economic situation is changing significantly.
病気の初期様相を見逃してはいけない。
You must not overlook the early signs (aspects) of the disease.
In philosophy, it can refer to modality — the modal aspects concerning possibility, necessity, etc.
哲学の授業で『様相』という概念（モダリティ）について学んだ。
In the philosophy class I learned about the concept of 'modality' (yōsō).