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| Opern f | |||
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| Oper f | |||
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| Oper f (One of the music genres that appears under Genre classification in Windows Media Player library. Based on ID3 standard tagging format for MP3 audio files. Winamp genre ID 103) | |||
| English thesaurus | |||
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| oil pollution environmental risk assessment | |||
| operational analysis | |||
| Open Process Engine For Reliable Activities | |||
| operational analysis | |||
| out-of-pile expulsion and reentry apparatus | |||
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| o | |||
| A powerful type of drama, where a majority of the words are solely sung. | |||
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operas : 36 phrases in 11 subjects |
| Art | 2 |
| British usage, not spelling | 1 |
| Construction | 2 |
| Cultural studies | 2 |
| Education | 1 |
| General | 20 |
| Industry | 1 |
| Informal | 2 |
| Medical | 2 |
| Optics branch of physics | 2 |
| Social science | 1 |