noun
lower abdomen; hypogastrium
Refers to the lower part of the abdomen, below the navel. Used in medical and everyday contexts.
下腹部に痛みを感じる。
I feel pain in my lower abdomen.
下腹部の脂肪を落とす運動をしている。
I'm doing exercises to lose lower belly fat.
お腹 is a common, informal word for belly or stomach, not as anatomically precise as 下腹部.
Compound of 下 (か, 'lower') + 腹部 (ふくぶ, 'abdomen').