Cottonwood/ˈkɑːtnwʊd/ Definition 1 of 2Pro Tip 1/3Seasonal Context Cottonwood is associated with spring when seeds disperse like cotton fluff. The cottonwood fluff in the air indicates springtime is here. Pro Tip 2/3Outdoor Activities Cottonwood trees are common in parks and camping areas, providing shade and scenery. They pitched their tent under a towering cottonwood. Pro Tip 3/3Allergy Indicator Cottonwood pollen can be an allergen; important for health references. His allergies flared up near the blooming cottonwoods.