system
A chat on 4chan
human
The human spine is made of 33 individual bones or vertebrae

In the Pythagorean system, 33 is the highest of the three master numbers which do not get reduced to a single number

In thesums of powers,thesum of three cubes(a3+ b3+ c3)is 33

33 is the largest number that is not a sum of distinct triangular numbers

Water boils at 33 degrees according to the temperature scale devised by Isaac Newton

The wordamenhas a value of 33 in simple English gematria: (a=1)+(m=13)+(e=5)+(n=14) = 33

Arsenic a.k.a.The Poison of Kingshas an atomic number of 33. Its alchemical symbollooks like a partially formed Star of David

Jesus was 33 years old when he was crucified and resurrected 

Islamic prayer beads are generally arranged in 3 sets of 33 for a total of 99 beads corresponding to the 99 Attributes of Allah

The second level of heaven in Buddhism is named Trāyastriṃśa from the numeral trayastriṃśat meaning '33' and can be translated in English as 'belonging to the thirty-three devas/gods' 

The divine name Elohim appears 33 times in the story of creation in the opening chapters of Genesis 

There are 33 deities in the Vedic or ancient Hinduism religion, etc.
gpt
Nice
but still, it doesn't really explain its meaning
human
This basically.


>but still, it doesn't really explain its meaning
That is the meaning. The number 3 is an important religious number all-around (trinity, etc). As with any occult symbol, number, whatever, they all mean different things to different people. The source of symbols being 'occult' (hidden) was due to the church finding any religious parallels to any other culture as blasphemous. In today's world of freedom of thought and religion the symbols are just meme markers from a time long past
gpt
But why are they still be used like in 
human
Some people think it's a certain thing. Usually though it's a sign used by demonically possessed people. The main conclusion of why people believe it means a 'certain thing' is understandable - but, once you get past the mysteries and see the evidence of things you realize it's mostly an indicator of demonically possessed people. Of course there are noobs who use religious symbols/numbers whether they just read the bible a lot or whatever.