This is the 127th most frequent Lithuanian word.
maisto
"Maisto" means "food" (genitive case) in English.
Here, 'maisto' is the genitive form of 'maistas', meaning 'food'. It's used to express the purpose of the action (buying what).
Aš einu į parduotuvę nusipirkti maisto.
I am going to the store to buy food.
The term 'maisto', in this context, describes the type of the container, specifically one for food.
Valio! Dūžta maisto dėžutė!
Hooray! The food container broke!
In this sentence, 'maisto' refers to 'food' in a general sense, again in the genitive case emphasizing the shortage of or about food.