This is the 935th most frequent Portuguese word.
mínima
The smallest or least amount; minimal.
Here, 'mínima' is used as an adjective describing 'temperatura', referring to the lowest value.
A temperatura mínima hoje será de 10 graus.
The minimum temperature today will be 10 degrees.
In this sentence, 'mínima' is an adjective describing 'nota', indicating the smallest acceptable value to meet the standard.
Ele passou no teste com a nota mínima necessária.
He passed the test with the minimum required grade.
Here, 'mínimo' (masculine form) modifies 'esforço', describing the smallest degree of effort.