Green’s Dictionary of Slang

1. a drop of mucus lodged at the opening of a nostril and hanging there before removal; thus dew-dropped adj.

1781		W. Cowper ‘Truth’ in Works (1863) 147: With slip-shod heels & dewdrop at his nose.
1939		H.E. Bates My Uncle Silas 7: Snotty little bit of a chap, red hair, always had a dew-drop on the end of his nose.
1950		(con. 1936–46) K.S. Prichard Winged Seeds (1984) 369: Rosy Ann couldn’t keep the dew-drops off the end of her nose. She was sniffin’ and swallowin’ the hot soup as fast as she could.
1950		C. Harris Three-Ha’Pence to the Angel 96: A dew-dropped tramp would perhaps sell them a pair of laces.
1951		T. Driberg Best of Both Worlds (diary) 3 May (1953) 32: A venerable figure [with] a dew-drop poised on the end of his rosy nose.

2. (Aus.) a tear.

1895

Crowe Aus. Sl. Dict. 23: Dew Drops, tears.

3. the lock on a gas-meter [it also ‘hangs down’].

1910

Sessions Papers 17 Oct. in DSUE (1984) I am going to knock off that ‘dewdrop’ meaning the lock of the gas meter.