Céntimo vs. centavo
The words 'céntimo' and 'centavo' refer to the unit of a currency in different Spanish-speaking regions. They both signify a fractional monetary unit that is equal to one hundredth of the basic unit of the currency.
Céntimo
'Céntimo' is the Spanish term for one hundredth of a euro, primarily used in Spain. In certain other contexts it may also mean one hundredth of a local currency (e.g., in Venezuela, Peru, Paraguay and Costa Rica).
Este caramelo cuesta diez céntimos.
(This candy costs ten cents.)
No tengo un céntimo en mi bolsillo.
(I don't have a cent in my pocket.)
La entrada al museo cuesta dos euros y cincuenta céntimos.
(Entrance to the museum costs two euros and fifty cents.)
Centavo
'Centavo' is used in many Latin American countries (e.g., Mexico, Argentina or Colombia), particularly those using pesos. It refers to one-hundredth of their basic monetary unit.
Esta manzana cuesta cinco centavos.
(This apple costs five cents.)
No tengo ni un centavo en mi cuenta bancaria.
(I don't have a single cent in my bank account.)
El precio del boleto es diecisiete pesos con cuarenta y cinco centavos.
(The ticket price is seventeen pesos and forty-five cents.)
Summary
'Céntimo' and 'centavo' both mean 'cent', representing one hundredth of a basic monetary unit, but are used in various Spanish-speaking regions. 'Centavo' is commonly used for fractional units of currencies like peso in Latin America while 'céntimo' is typically associated with the Euro denominations, mainly used in Spain.