This word literally translates to "film membrane".
Here are some other related terms you might encounter:
* நுரையீரல் திரைப்படலம் (nuraiyaeril thiraipadalum): Lung diaphragm
* வயிற்றுத் திரைப்படலம் (vayitruth thiraipadalum): Abdominal diaphragm
It's important to note that depending on the context, other terms like "சுவாசக் கருவி" (suvaasak karuvi) - meaning "breathing instrument" - might also be used to refer to the diaphragm.