Plata vs. plato
While the Spanish words plata and plato are separated by only one letter, they have completely different meanings and are not interchangeable. The key difference lies in their gender (la plata is feminine, el plato is masculine) and what they refer to: plata is silver or money, while plato is a plate or a dish of food.
Plata
A2This feminine noun refers to the precious metal silver. In many Spanish-speaking regions, especially in Latin America, it is also a very common colloquial term for money or cash.
Mi abuela tiene unos pendientes de plata muy antiguos.
(My grandmother has some very old silver earrings.)
Los cubiertos de la cena elegante eran de plata maciza.
(The cutlery for the elegant dinner was made of solid silver.)
La medalla del segundo lugar en la competición es de plata.
(The second-place medal in the competition is made of silver.)
No me alcanza la plata para comprar ese teléfono.
(I don't have enough money to buy that phone.)
¿Me puedes prestar algo de plata hasta la próxima semana?
(Can you lend me some money until next week?)
Ganar la lotería significa tener mucha plata de repente.
(Winning the lottery means having a lot of money suddenly.)
Plato
A1This masculine noun refers to a plate, the physical dish you eat from. It is also used to mean a dish or a course in a meal, referring to the food itself.
Ten cuidado, no vayas a romper el plato de porcelana.
(Be careful, don't break the porcelain plate.)
Por favor, coloca los platos sucios en el lavavajillas.
(Please, put the dirty plates in the dishwasher.)
Necesito un plato hondo para la sopa.
(I need a deep plate for the soup.)
La paella es mi plato español favorito.
(Paella is my favorite Spanish dish.)
Para el plato principal, quiero el pescado del día.
(For the main course, I want the fish of the day.)
El menú del restaurante ofrece una gran variedad de platos.
(The restaurant's menu offers a wide variety of dishes.)
Summary
In short, plata (feminine) is the metal silver or a common slang term for money. Plato (masculine) is either the physical plate you eat from or a prepared dish of food. A simple way to remember is: you eat a plato of food, and you pay for it with plata.