21-letter words containing o, d, p, r, i
- wet collodion process — a photographic process, in common use in the mid-19th century, employing a glass photographic plate coated with iodized collodion and dipped in a silver nitrate solution immediately before use.
- whip-and-tongue graft — a graft prepared by cutting both the scion and the stock in a sloping direction and inserting a tongue in the scion into a slit in the stock.
- white-crowned sparrow — a North American sparrow, Zonotrichia leucophrys, having black and white stripes on the head.
- wholesale price index — an indicator of price changes in the wholesale market
- wildlife photographer — someone that specializes in taking photographs of wild animals, especially in their natural habitats, and plants
- window of opportunity — limited chance to do sth
- xeroderma pigmentosum — a rare inherited disease characterized by sensitivity to ultraviolet light, exposure resulting in lesions and tumors of the skin and eyes.
- yellow lady's-slipper — a showy orchid, Cypripedium calceolus, of eastern North America, having purple-tinged yellow flowers with an inflated lip petal.