dropper
Concise Oxford English Dictionary © 2008 Oxford University Press:
dropper/ˈdrɒpə(r)/
▶noun
- 1 a short glass tube with a rubber bulb at one end, for measuring out drops of liquid.
- 2 Austral./NZ & S. African a light vertical stave in a fence.
- 3 Fishing a line or loop of filament attached to a main line.
'dropper' also found in these Oxford entries:

