plexor; plessor; percussor
A medical instrument used in percussion examination; a small hammer-like device for tapping the body to assess underlying structures.
医師は打診器で患者の胸を軽く叩いた。
The doctor lightly tapped the patient's chest with a plexor.
Compound of 打診 (percussion, from 打 'strike' + 診 'examine') and 器 ('instrument').