DISTEND

expand

swell out

/become wider

cause to expand/swell as if by internal pressure

"the distended bellies of the starving cows"

"the gas distended the animals bodies"

"the way that her belly distended it gave away the pregnancy she was attempting to dissemble."

"the pipes had slowly distended where the gas had been clogged up."

"He had been hoping that by running water at a high pressure through the hose it would distend and reach it's original width."