Each country in the European Union has its own definition of a forest and the European Commission has defined forestland as having at least 20% canopy closure (10% in the Mediterranean forests) and a minimum area of 0.5 ha. (1 ha. = 0.01 kmÂ²). Elsewhere, the definition of a tree can vary.
Lunula: the crescent-shaped area at the base of the human fingernail.
A cannula (from Latin little reed ; plural cannulae or cannulas) is a tube that can be inserted into the body, often for the delivery or removal of fluid or for the gathering of data.