Barriga vs. vientre vs. panza
The Spanish language, like every other language, has multiple words that can be used to represent similar concepts. In the case of the abdomen or belly, 'barriga', 'vientre' and 'panza' are commonly used interchangeably but they have nuanced differences in their meanings depending on the region and context.
Barriga
'Barriga' refers more specifically to the lower part of the abdomen, especially when it is inflated or swollen. It is a neutral term often used in everyday conversations.
Después de comer, mi barriga se hinchó.
(After eating, my belly swelled up.)
Tienes que hacer ejercicios para reducir la barriga.
(You have to do exercises to reduce your belly.)
Vientre
'Vientre' is a rather formal or scientific term for describing the lower front part of the human body and the organs in it. It's also often used in reference to pregnancy.
El bebé se movía frecuentemente en el vientre de su madre.
(The baby often moved in its mother's womb.)
El médico examinó mi vientre para verificar si había alguna anomalía.
(The doctor examined my abdomen to check if there is any anomaly.)
Panza
'Panza' is an informal and colloquial term for stomach or potbelly, especially when it is prominent or rounded. The use of this term can vary regionally.
Mi abuelo siempre tenía una gran panza después de cenar.
(My grandfather always had a big belly after dinner.)
No puedo ponerme estos pantalones porque marcan demasiado la panza.
(I can't put on these pants because they mark my belly too much.)
Summary
In Spanish, although 'barriga', 'vientre', and 'panza' all refer to the lower front part of the human torso, their usage varies depending on formality levels, context, and regional differences. 'Barriga' is a general term commonly used to describe a swollen or inflated abdomen. 'Vientre' has a more formal or scientific tone and is often associated with pregnancy. On the other hand, 'panza' is a colloquial term mainly used to describe a prominent or rounded stomach.