Einfällen

Einfüllen is a German verb meaning to fill into a container or space by introducing a substance. It is commonly used when liquids, powders, or gases are poured or added into another object, such as oil in a motor, water into a bottle, or juice into a glass. The sense is movement into a receptacle rather than simply “filling.”

Grammatical note: einfüllen is a separable verb. In the present tense you say: ich fülle ein, du füllst ein, er füllt ein, wir füllen ein, ihr füllt ein, sie füllen ein. In the perfect tense the common construction is with haben: ich habe Öl in den Motor eingefüllt. In subordinate clauses the prefix can appear at the end, e.g., Ich fülle das Öl in den Motor ein. The infinitive is einfüllen, and the past participle is eingefüllt.

Typical usage patterns include: etwas in etwas einfüllen (to fill something into something), or etwas in etwas einfüllen (to fill a container with a substance). There are related verbs with different nuances, such as befüllen (to fill up a container completely) and auffüllen (to top up or refill). A contrast is ausfüllen, which is usually used for completing forms or fields, not for pouring liquids.

Examples: Öl in den Motor einfüllen; Wasser in die Flasche einfüllen; die Pfanne mit Öl einfüllen. In scientific or technical contexts it also appears when liquids or powders are added to equipment or reaction vessels.

Etymologically, einfüllen combines the prefix ein- with füllen (to fill) and belongs to the family of separable prefix verbs in German.