This is the 127th most frequent Russian word.
марта
The Russian word "марта" translates to "March" (the month) in English.
In this sentence, 'марта' is the genitive case of the noun 'март' (March), used to denote the date.
Сегодня первое марта.
Today is the first of March.
Here, 'Марта' is a proper noun, the name of a person, in the genitive case to indicate possession.
Мы отметили день рождения Марта.
We celebrated Marta's birthday.
In this sentence, 'Марте' (to Marta) indicates the dative case, used to show the indirect object of the action.