[stoh-muh-dee-uh
m, stom-uh-] 
[-dee-uh] . Embryology. | a depression in the ectoderm of the oral region of a young embryo, which develops into the mouth and oral cavity. |
| sto·mo·de·um also sto·mo·dae·um (stō'mə-dē'əm) n. pl. sto·mo·de·a also sto·mo·dae·a (-dē'ə) The anterior or oral portion of the alimentary canal of an embryo. [New Latin : Greek stoma, mouth + Greek hodaios, on the way (from hodos, road).] sto'mo·de'al (-dē'əl) adj. |
stomodeum sto·mo·de·um (stō'mə-dē'əm)
n.
A midline ectodermal depression ventral to the embryonic brain and surrounded by the mandibular arch. It becomes continuous with the foregut and forms the mouth.