Puerta vs. puerto
The Spanish words puerta and puerto are often confused by learners due to their similar spelling. However, they are distinct nouns with different genders and completely separate meanings.
Puerta
A1Puerta is a feminine noun that means door. It refers to the movable barrier used to open and close an entrance to a building, room, or vehicle. By extension, it can also mean gate.
Por favor, cierra la puerta cuando salgas.
(Please, close the door when you leave.)
La puerta del coche no abre desde afuera.
(The car door doesn't open from the outside.)
Pintamos la puerta del jardín de color azul.
(We painted the garden gate blue.)
El conocimiento de idiomas te abrirá muchas puertas.
(Knowing languages will open many doors for you.)
Nuestro vuelo sale por la puerta de embarque B12.
(Our flight departs from boarding gate B12.)
Puerto
A2Puerto is a masculine noun that means port or harbor, a place where ships dock. It can also refer to a mountain pass or a connection point on an electronic device, like a USB port.
El crucero llegará al puerto a las ocho de la mañana.
(The cruise ship will arrive at the port at eight in the morning.)
En invierno, el puerto de montaña a menudo está cerrado por la nieve.
(In winter, the mountain pass is often closed due to snow.)
Mi ordenador tiene tres puertos USB.
(My computer has three USB ports.)
El Callao es el principal puerto marítimo del Perú.
(Callao is the main seaport in Peru.)
Después de un largo viaje, su casa era un puerto seguro.
(After a long journey, his house was a safe harbor.)
Summary
In summary, the essential difference is in their gender and meaning. Puerta is a feminine noun for a door or gate. In contrast, puerto is a masculine noun for a port, harbor, or mountain pass. The final vowel is the key to telling them apart: the -a in puerta signals an entryway, while the -o in puerto signals a place of arrival or connection.