Three live senses: (1) hardware/software self-test (POST in computers, BIT in equipment), (2) medical self-exam (breast, skin), (3) classical sense of self-restraint or moral self-examination. Modern usage is dominantly the first two.
memory
自 (self) + 检 (examine/check). Compare 体检 (tǐjiǎn, physical exam by a doctor) — same 检, but the agent shifts from doctor to self.
