This is the 62nd most frequent Portuguese word.
diz
"Say" or "says" (third person singular of "dizer").
Here, 'diz' is used in a third-person singular context to indicate direct speech or statement.
Ele diz que vai chover amanhã.
He says it will rain tomorrow.
In this instance, 'diz' is used in a general sense, as part of a proverb, implying speaking or expressing an idea.
Quem diz o que quer, ouve o que não quer.
Who says what they want, hears what they don't want.
Here, 'diz' is used figuratively to describe what information is shown or expressed on a display.