Aprikose vs. Marille
The difference between the German words Aprikose and Marille is entirely regional, as both words mean exactly the same thing: an apricot. The fruit is referred to as Aprikose in standard German, which is mostly used in Germany and Switzerland, whereas Marille is the traditional term used in Austria and the southern German region of Bavaria.
Aprikose
A2The word Aprikose refers to the apricot fruit and is the standard vocabulary used throughout most of Germany and Switzerland.
Ich koche heute Marmelade aus frischen Aprikosen.
(I am making jam from fresh apricots today.)
Meine Oma backt jeden Sommer einen leckeren Kuchen mit Aprikosen.
(My grandma bakes a delicious cake with apricots every summer.)
Der Supermarkt bietet getrocknete Aprikosen als gesunden Snack an.
(The supermarket offers dried apricots as a healthy snack.)
Aprikosen wachsen am besten in warmen und sonnigen Regionen.
(Apricots grow best in warm and sunny regions.)
Der Joghurt schmeckt nach Pfirsich und Aprikose.
(The yogurt tastes like peach and apricot.)
Marille
B2The word Marille describes the exact same apricot fruit, but it is the preferred local dialect term used in Austria and the German state of Bavaria.
Im Urlaub in Wien habe ich traditionelle Knödel mit frischen Marillen gegessen.
(On vacation in Vienna, I ate traditional dumplings with fresh apricots.)
Der Bauer aus der Wachau verkauft süße Marillen auf dem Markt.
(The farmer from the Wachau region sells sweet apricots at the market.)
Zum Nachtisch gibt es Palatschinken mit hausgemachter Marmelade aus Marillen.
(For dessert, there are pancakes with homemade jam made from apricots.)
Dieser preisgekrönte Schnaps wird aus überreifen Marillen gebrannt.
(This award-winning schnapps is distilled from overripe apricots.)
Hast du schon einmal den berühmten Likör aus Marillen probiert?
(Have you ever tried the famous liqueur made from apricots?)
Summary
To conclude, there is no biological or culinary difference between an Aprikose and a Marille. Your choice of word simply depends on the geographical location: use Aprikose when conversing in Germany or Switzerland, and switch to Marille when you are visiting Austria or Bavaria.