Rubric means abbreviated signature of someone or a little note. The word comes from the Latin "initial", which refers to "red, red".
In ancient manuscripts and codices, a rubric designated the letter or initial line of a chapter written in red. The titles of Civil Law books are designated as a rubric. Previously the titles of these books were written in red.
The term rubric also designates a small written commentary that has the function of guiding something that is being performed or a reminder for later use. Rubrics are used in film or theater scripts to indicate gestures or movements of actors, in musical guidelines or in liturgical texts, to guide celebrations. Rubric also corresponds to an annotation in red, in religious books, for liturgical orientation.
In industry, rubric is a reddish clay used as a dye or as a polish. This material is also used in crude-looking paintings or prints. In the past, carpenters used almagre to mark the wood before sawing. Likewise, in ancient times, this reddish clay was also used on wounds to stop the blood.
In typography, rubric designates the change made to the typographic plate to be used later in another work.
Rubric or Rubric
For any rubric meaning, the correct spelling of the word is without u stress. Rubric is a serious word and therefore the correct pronunciation should be "initial" and not "rubric". So write and say initial it is a mistake.