The word грамота has different meanings:
charter (the old word for a "contract"), exactly as you found it in the dictionary. This word is still used at school when you get a diploma because you were good at something or participated in a contest.
В школе мне дали почëтную грамоту за участие в соревнованиях по волейболу.
I got a diploma at school for participation in a volleyball competition.
literacy, reading and writing, it´s the most widespread meaning.
В школе нас учат грамоте.
At school we learn how to read and write.
Компьютерная грамота очень важна в наше время.
Computer skills are very important nowadays.
Russian Language Teacher.