‘针孔’ (zhēn kǒng) literally means ‘needle hole’ — combining 针 (zhēn), ‘needle’, and 孔 (kǒng), ‘hole’ or ‘aperture’. It refers to a very small, round opening, typically formed by piercing with a fine needle or similar sharp object. While it can describe any tiny man-made puncture (e.g., in fabric or paper), in biological and veterinary contexts it most commonly denotes the tiny perforation left by an acupuncture needle or injection — especially when describing how animals respond to such procedures.

The term is frequently used in traditional Chinese medicine (TCM) discussions involving animal treatment, as well as in veterinary reports describing minimal-invasive procedures. Unlike generic terms for ‘hole’ like 洞 (dòng), 针孔 emphasizes both the cause (needle puncture) and the size (microscopic to barely visible). It carries neutral-to-technical register and appears often in clinical notes, care instructions, or observational descriptions of healing processes.