
Peach-strawberry cordial is a sweetened, acidified fruit concentrate of peach and strawberry, poured into a drink rather than diluted. The acid is what makes it a cordial: it sharpens as well as sweetens.
Peach and strawberry syrups mixed to taste is the closest rebuild, and it lets you set the balance the bottle chose for you. Either fruit alone gives half the drink and often enough of it. Fresh fruit macerated with sugar gives more aroma and none of the shelf life.
An American cordial
The word means a sweetened liqueur in the US: alcoholic, poured by the measure. A recipe asking for a peach cordial can mean either product, and the quantity tells you which.
Peach schnapps
Alcoholic and much less fruity than the name suggests, since most of it is flavored neutral spirit; it replaces neither the sweetness nor the fresh fruit note.
Sealed and commercial, months; open, the fridge. Homemade lasts a couple of weeks refrigerated and peach is the part that fades first, so a blend that tasted balanced when you made it drifts toward strawberry as it ages.