What is diaphragm? Md. Saifur Rahman The diaphragm is a muscular sheet that separates the thoracic cavity from the abdominal cavity.Read more:What is glass fire? What is the Paris accord? What is a diaphragm? What is interphase? What is histology? What is the endocrine gland? What is called nucleotide? What is cell division? What is karyokinesis? What is osmoregulation? What does attraction fiber mean? What is spindle fiber? What is cytokinesis?