- 2 Ovens (baking equipment)
- 38 Overbrook
- 14 Overbrook Avenue
- 9 Overbrook Park, Pennsylvania
- 6 Overbrook School for the Blind
- 16 Overhead views
- 12 Overington Street
- 1 Overlooks
- 2 Overproduction
- 14 Overs, John, 1808-1844
- 1 Oversewing machine
- 1 Ovid, 43 B.C.-17 A.D. or 18 A.D.
- 5 Owen, Richard, 1804-1892
- 1 Owen, Robert
- 33 Owls
- 1 Oxberry, William Henry, 1808-1852
- 37 Oxen
- 7 Oxford & Lower Dublin Poor House
- 6 Oxford Avenue
- 10 Oxford Circle, Pennsylvania
- 1 Oxford Iron & Steels Works-William & Harvey Rowland
- 1 Oxford Race Course
- 16 Oxford Street
- 1 Oxford Street Market
- 5 Oysters
