This is the 13284th most frequent Russian word.
морю
"Морю" is the dative case form of "море," meaning "to the sea" or "for the sea."
The word 'морю' is in the dative case, indicating the direction 'to' or 'towards the sea'.
Я еду к морю на выходные.
I am going to the sea for the weekend.
Here, 'морю' is in the dative case, showing the indirect object, as the sea is personified as enjoying the good conditions.
Морю нравятся хорошие погодные условия.
The sea likes good weather conditions.
In this example, 'морю' is in the prepositional case, describing the location 'on the sea' (though often 'по' can use different cases, in this context it reflects movement along the sea).