Bamboos are a diverse group of mostly evergreen perennial flowering plants making up the subfamily Bambusoideae of the grass family Poaceae. Giant bamboos are the largest members of the grass family, in the case of Dendrocalamus sinicus individual culms reaching a length of 46 meters, up to 36 centimeters in thickness and a weight of up to 450 kilograms. The internodes of bamboos can also be of great length. Kinabaluchloa wrayi has internodes up to 2.5 meters in length. and Arthrostylidium schomburgkii with lower internodes up to 5 meters in length, exceeded in length only by papyrus. By contrast, the culms of the tiny bamboo Raddiella vanessiae of the savannas of French Guiana are only 10–20 millimeters in length by about two millimeters in width. The origin of the word "bamboo" is uncertain, but it probably comes from the Dutch or Portuguese language, which originally borrowed it from Malay or Kannada.

In botany, an evergreen is a plant which has foliage that remains green and functional throughout the year. This contrasts with deciduous plants, which lose their foliage completely during the winter or dry season.