The litre or liter (see spelling differences) is a unit of volume. There are two official symbols: the Latin letter L in lower and upper case (l and L). The lower case L is also often written as a cursive ℓ, though this symbol has no official approval by any international bureau. Although the litre isn't an SI unit, it's accepted for use with the SI, Bureau International des Poids et Mesures, 2006, p. 124. ("Days" and "hours" are examples of other non-SI units that SI accepts.) and has app… (More on Millilitre)