Peito vs. tórax
In Portuguese, both peito and tórax can be translated as chest, but they are used in different contexts. Peito is the common, everyday word, while tórax is a more formal and technical term used primarily in medical and scientific fields.
Peito
A1Peito is the most frequently used word for chest. It refers to the upper front part of the torso. It can also be used more broadly to refer to a person's breast, a cut of meat (brisket), or metaphorically to the heart as the seat of emotions.
Ele sentiu uma dor forte no peito depois de correr.
(He felt a strong pain in his chest after running.)
A camisa nova tem um bordado no peito.
(The new shirt has embroidery on the chest.)
A mãe deu o peito ao filho.
(The mother breastfed her son.)
Ele abriu o peito e contou todos os seus segredos.
(He opened his heart and told all his secrets.)
Para o churrasco, compramos um belo pedaço de peito de boi.
(For the barbecue, we bought a nice piece of beef brisket.)
Ele estufou o peito com orgulho ao receber o prêmio.
(He puffed out his chest with pride upon receiving the award.)
Tórax
B2Tórax is the anatomical and medical term for the chest, referring to the entire chest cavity that encloses the rib cage, heart, and lungs. Its usage is almost exclusively formal, technical, or scientific.
O médico pediu uma radiografia do tórax para verificar os pulmões.
(The doctor ordered a chest X-ray to check the lungs.)
Na aula de anatomia, estudamos os músculos do tórax.
(In anatomy class, we studied the muscles of the thorax.)
O paciente sofreu um trauma grave no tórax durante o acidente.
(The patient suffered severe trauma to the thorax during the accident.)
O corpo de um inseto é dividido em cabeça, tórax e abdômen.
(An insect's body is divided into a head, thorax, and abdomen.)
Os exercícios de respiração ajudam a expandir a caixa do tórax.
(Breathing exercises help expand the chest cavity.)
Summary
In essence, use peito for everyday conversations about the front of your chest, pain, emotions, or even breasts. Use tórax when you are in a formal, medical, or scientific context, referring to the entire anatomical structure of the chest. Think of peito as chest and tórax as thorax.