投下

(1)the act of dropping something; "they expected the drop would be successful"

(2)何かを落とす行為

(3)delivery of supplies or equipment or personnel by dropping them by parachute from an aircraft; "until then, front line troops will be supplied by airdrop"

(4)補給品または機材または人員の配送方法で、航空機からパラシュートで落下させることにより行う

(1)