This is the 5502nd most frequent Japanese word.
おお
"おお" is an exclamation meaning "Oh!" or "Wow!" in Japanese, expressing surprise or admiration.
Interjection expressing surprise
おお、これはすばらしい！
Oh, this is wonderful!
Used as part of 'おおきく' meaning 'loudly' or 'largely'
おおきく声を出して読んでください。
Please read aloud with a loud voice.
Used as the adjective 'おおきい' meaning 'big'