This is the 248th most frequent Bulgarian word.
първи
"Първи" means "first" in English.
Here, 'първи' is used as the ordinal number 'first' to describe sequence.
Той беше първият, който пристигна.
He was the first to arrive.
In this sentence, 'първи' describes the initial attempt, again as an ordinal reference.
Успях от първия опит.
I succeeded on the first try.
Here, 'първи' is used in plural form to indicate initial days in a sequence.