(1):

(a. & n.) Same as Due, or Duty.

(2):

(n.) Moisture from the atmosphere condensed by cool bodies upon their surfaces, particularly at night.

(3):

(n.) Figuratively, anything which falls lightly and in a refreshing manner.

(4):

(n.) An emblem of morning, or fresh vigor.

(5):

(v. t.) To wet with dew or as with dew; to bedew; to moisten; as with dew.