What Is Full Form Of Opd?

I could use more background on this, but here are a few:

• Ottawa Police Dept, Omaha PD.
• Once Per Day (very uncommon meaning -- shuold be qd.)
• Officially Pronounced Dead
• Obnoxious Personality Disorder (never heard this one myself).
• Outpatient Dept.

Or could it be a mispelling of COPD -- Chronic Obstructive Pulmonary Disorder?