noun
liter
A1
Liter: Unit of volume 'liter'. German noun masculine: der Liter. Plural usually Liter (no change); genitive singular des Liters. Dative plural den Litern. Commonly used with quantities (zwei Liter Wasser). Regular plural form; note genitive adds -s in singular: des Liters.
Examples
Ich brauche zwei Liter Wasser für das Rezept.
I need two liters of water for the recipe.
Ein Liter Milch kostet einen Euro.
One liter of milk costs one euro.
Der Koch fügte zwei Liter Brühe hinzu, damit die Suppe dicker wurde.
The cook added two liters of broth so that the soup became thicker.
Details
Mnemonics
A bottle labelled '1 L' to remember 'Liter' = liter
sounds like 'litter' — imagine a litre bottle dropping litter
der (often) — think of 'der Liter' like other masculine units (der Meter)
Notes
Can be used with both der and das regionally; default/common usage is der Liter. Plural often unchanged: Liter.