The spelling of the word "OPD OC" is based on the International Phonetic Alphabet (IPA). The letters "O," "P," and "D" represent three separate speech sounds, pronounced as /ɑ/, /p/, and /d/ respectively. The two letters "O" and "C" stand for another sound, pronounced as /o/ and /k/ respectively. The word "OPD OC" does not have any specific meaning in English or any other language. However, it can be used as a phonetic example to study and understand the English language's sound system.