This is the 6006th most frequent Russian word.
служил
"Служил" means "served" (past tense of "to serve").
Here, "служил" is used to describe someone performing military service temporarily.
Он служил в армии три года.
He served in the army for three years.
In this sentence, "служил" means to fulfill a function or role.
Этот предмет служил нам верой и правдой много лет.
This item served us faithfully for many years.
Here, "служил" refers to being employed in a non-military position.