Many verbs, like bauen or braten can be combined with an- to form verbs like anbauen or anbraten. However, in some cases there are variants of these verbs that take aus for example ausbauen or ausbraten.

Is there any rule for deciding whether a verb takes aus or an? They appear to mean exactly the same, though in some cases one would (conventionally?) say Wein ausbauen rather than Wein anbauen, but in other cases one would say Kartoffeln anbauen rather than Kartoffeln ausbauen. Or is this related to dialects from the speakers?

  • "aus" and "an" look similar but that's all. They are not closer related than any other pair of prefixes.
    – RHa
    Jun 20, 2017 at 9:22

2 Answers 2


These are separate verbs. One can try to deduct the meaning from the built-in preposition but there are transferred meanings involved which don't seem reasonable at first glance. Or maybe not even anytime later.

bauen (to build)

anbauen (to attach something (by building); to grow fruits and vegetables)

The preposition an means tight to, so attaching something is straight forward. But why grow fruits and vegetables? NO ONE KNOWS.

ausbauen (to add interior; to intensify; to refine)

The preposition aus means out of. Why is adding interior, intensify or refine out of? NO ONE KNOWS.

Uh, and by the way, wine is also being angebaut. That means to grow the vines. While ausbauen means to refine the product by putting it in storage for months to years before selling.

And of course, a whole range of prepositions and other prefixes can be combined with bauen, too:

einbauen (to build something into something else)

abbauen (to remove something previously attached)

umbauen (to rebuild something)

überbauen (to build something on top of an older structure in the ground)

zubauen (to close the last gaps by building)

erbauen (to construct)

verbauen (to build too much stuff into a compartment)

vorbauen (to prepare oneself)

etc etc.

Treat them all as separate verbs. And for all the other verbs, too.

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    "The preposition an means tight to, so attaching something is straight forward." - well, another common meaning of the an prefix in verbs is that the action is just started, not completed to its end (antesten, anbrechen, ...). And yet another one refers to the state of something being "(switched) on" (anschalten, anmachen, angehen, ...). Jun 18, 2017 at 21:10
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    "Treat them all as separate verbs." - in one way, yes. But, as pointed out in my above comment, there are indeed various common meanings for prefixes that can also help to deduce the meaning of a verb. The tricky part is that often, "prefix + root" is either an "official" combination with a specific meaning where the meaning of the prefix may be non-obvious or deviate from the general case, or "prefix + root" is not an "official" combination, in which case the combination can still be formed ad-hoc, with the prefix using its common meaning (or one of them, if there are more than one). Jun 18, 2017 at 21:13
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    "but neither of them matches growing fruits" - I'm not so sure about that. You don't build fruits, but you "lay their foundations". Thus, you start their construction process, which could well match with the first meaning of "an" that I outlined in my comment. Jun 18, 2017 at 21:18
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    @Janka: the verb is "anbauen". "Ich baue an" is a conjugation of the same verb, "to grow". Where do you grow? For instance on a field. So "ich baue auf meinem Acker Kartoffeln an" means "I grow potatoes on my field". Jun 18, 2017 at 23:22
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    @Janka: they not only resemble prepositions, they are derived from prepositions. Often, the meaning of the preposition is somehow related to the meaning of the verb prefix, although through the times, that relation may have changed a lot and the prefix may have got a meaning of its own. But even if I hear a German word with a prefix I didn't know before, the prefix usually tells me what the meaning of the word is. For instance the prefix "zer-" often means something destructive, and the prefix "ver-" indicates change. "An-" often means adding something, and "ent-" indicates removal. Etc. Jun 18, 2017 at 23:31

It can be reasoned by two meanings: place or time.

Examples for "place":

  • anbauen: you put something there (either to grow sth. (put the seed/plants in the ground) or to mount (add another piece), German: etwas da heran bauen

Examples for "time":

  • ausbauen: you continue to build, means out of a certain time until the end
  • anbraten: you start to roast (the beginning, German: Anfang)
  • ausbraten: you continue to roast, means out of a certain time until the end

You see (especially with anbauen/anbraten) there is not logical rule which one is used, it has developed historically, you just have to learn the vocabulary. This answer just gives you a certain background for the reasons.

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