Learn Spanish words starting with 'O' A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Here is a list of the most commonly used Spanish words similar to English words starting with the letter O. In most cases, you would use the Spanish word as you would the English word. Click on the audio button to hear how the Spanish word is pronounced. You will see that Spanish words are pronounced as they are written. English Spanish obedient obediente obese obeso/a object objeto objective objetivo obligation obligación observe observar obstruct obstruir occasion ocasión occupied ocupado/a ocean océano offend ofender offer oferta office oficina organic orgánico organize organizar oxygen oxígeno