円筒 is read as えんとう (entou) and means cylinder.
えんとう
entou
えんとうずほう
cylindrical projection
えんとうけい
cylindrical
えんとうぷりんたー
barrel printer
えんちゅう
round pillar (esp. in buildings)
えんしゅう
circumference
えんりょう
round collar (of traditional Japanese clothing)
えんいき
yen bloc
えんばんじょうぶんし
disc-like molecule
えんだかふきょう
recession caused by the strong yen
えんあつき
flatbed cylinder press
えんけいげきじょう
amphitheater
えんぶつきょう
Won Buddhism