ABRACADABRA
It's not actually something someone made up it actually does have to do something with magic and it actually explains a concept or a type of magic. You might wonder which one but we're getting to that in due time. Most often you will find it in a fashion similar to this:
ABRACADABRA
ABRACADABR
ABRACADAB
ABRACADA
ABRACAD
ABRACA
ABRAC
ABRA
ABR
AB
A
Analyzing this construct we notice 3 things. First of all, each line loses one letter of the word. Each line is then moved to the right by a little. And last, this produces a triangle form. The upside-down triangle is a symbol of the female principle, the actual meaning of the word abracadabra is unknown.
And that's all the information we can get out of it so far.
The Concept of ABRACADABRA
The concept of this magical construct, if we may it call such is quite simple. You can see that with each new line one letter is gone. The idea behind this is to weaken the construct with each new line. For example, you could say you're scared of an exam in mathematics. Now you could technically do the same as with the ABRACADABRA:
MATHEMATICS
MATHEMATIC
MATHEMATI
MATHEMAT
MATHEMA
MATHEM
MATHE
MATH
MAT
MA
A
If you write each line with the intent to weaken the power of math if used correctly in a ritual it should take any fear or worry from you. Aside from that saying math instead of mathematics also makes it sound more casual after all, doesn't it? Though keep in mind since English is a common language and I assume people who visit my blog as of now speak English it wouldn't be the right choice to use the English word. It would be better to use a less commonly spoken language like Latin, Greek or Hebrew or any other for that matter but you get the idea.
Historical Usage
Appearances of the ABRACADABRA have it often connected with usage in medical environments. This is understandable. The idea of it is to weaken something. If you use it to weaken an illness or a medical issue such as the severity of an injury it's easier for the body to fix itself and regenerate. Something weak is easier to beat.
Conclusion
So technically whenever we want to weaken something or make something big and or strong small and insignificant this concept can help us. Aside from that, it's just another example of how magic works and something one should know or have heard of.
So don't make a big deal out of it.Oh god, that was bad... I'm already starting to bring bad jokes and puns like Matpat from Game Theory...