1. US: the 4th Friday in September

Type of: day

Part of: Sep, Sept, September

• Xylaria polymorpha
• Xylariaceae
• xylem
• rydberg
• rydberg constant
• rydberg unit
• Rydberg's penstemon
• rye
• rye bread
• rye ergot
• rye whiskey
• rye whisky
• ryegrass
• Rynchopidae
• Rynchops
• ryot
• Rypticus
• Ryukyu Islands
• Ryukyuan
• Réaumur
• réchauffé
• rémoulade
• röntgen
• s
• S wrench