noun
breakfast, morning meal
A1
Means 'breakfast' or 'morning meal'. A neuter noun: das Frühstück. Plural is 'Frühstücke', though often used as a mass noun without plural when referring to the meal in general. Genitive singular 'des Frühstücks'. Common in compounds (Frühstück machen). Not irregular, standard declension.
Examples
Zum Frühstück servierte die Küche frische Brötchen, obwohl viele Gäste erst später kamen.
For breakfast the kitchen served fresh rolls, although many guests arrived later.
Das Frühstück war sehr gut.
The morning meal was very good.
Ich esse gern Frühstück.
I like having breakfast.
Details
Mnemonics
Picture a breakfast plate with a big 'das' tag.
Sounds like 'frew-shtook' -> 'food' in the morning.
das = imagine a neutral plate labeled 'das Frühstück'.
Notes
Frühstück is often uncountable, but plural 'Frühstücke' is used when talking about several breakfast occasions.