Refers to the lower part of the belly, often in casual or everyday contexts. Can imply a slightly protruding belly or the area below the navel.
Lately I feel like my lower belly has started to stick out.
腹筋を鍛えて下っ腹を引き締めたい。
I want to work my abs and tighten up my lower belly.
Lately, from lack of exercise, my lower belly has started to stick out.
I pulled in my lower belly before the photo was taken.
She's self-conscious about her lower belly bulging out.
My lower belly has hurt since this morning, so I went to the hospital.