diaphragmyoudaoicibaDictYouDict
diaphragm: [17] The etymological notion underlying diaphragm is of a sort of ‘fence’ or ‘partition’ within the body. It comes via late Latin diaphragma from Greek diáphragma. This in turn was a derivative of diaphrássein ‘divide off, barricade’, a compound verb formed from the intensive prefix dia- and phrássein ‘fence in, enclose’. Originally in Greek diáphragma was applied to other bodily partitions than that between the thorax and the abdomen – to the septum which divides the two nostrils, for instance.
diaphragm (n.)youdaoicibaDictYouDict
late 14c., from Late Latin diaphragma, from Greek diaphragma "partition, barrier, muscle which divides the thorax from the abdomen," from diaphrassein "to barricade," from dia- "across" (see dia-) + phrassein "to fence or hedge in." The native word is midriff. Meaning "contraceptive cap" is from 1933.