The symbol initially perplexed western observers as to why the Russian military had put the same letter on all their vehicles, but since then it has become a symbol of nationalist support for Russians.
On Sunday, a Russian artistic gymnast displayed a Z on the front of his leotard as he stood on the podium next to a Ukrainian athlete who had won the gold.
The International Gymnastics Federation denounced Ivan Kuliak's "shocking behaviour" during the medal ceremony at the Apparatus World Cup in Doha over the weekend and he now faces an investigation.
But the letter Z is not in the Russian Cyrillic alphabet, so what is the significance of the symbol?
Russian forces have used the letter Z as an identifying symbol on their vehicles in Ukraine but it was also spotted on Russian tanks in the Syrian civil war.The true military reason as to why they have decided to paint it on their vehicles is not known.
Some think it is just used to quickly identify Russian armour compared to enemy armour, or as a way to identify different task groups.
Some vehicles were spotted with O, X, or A on them, but the vast majority have featured the Z.
Senior International Correspondent John Irvine filmed dozens of Russian vehicles sporting the Z symbol as they left Mariupol
Others think it has a more symbolic meaning, with experts suggesting it could stand for "Za pobedy" (for victory) or as a reference to Ukrainian President Volodymyr Zelenskyy.Others have suggested it could mean "zapad" (West) as a reference to where in Russia it was originally stationed, but why they would choose to use a symbol not featured in their alphabet is unknown.Since it began appearing on the internet Russians seem to have taken the symbol to heart and it has been used as a propaganda tool by the Kremlin.
Numerous pictures have appeared on the internet of taxis and vans displaying the Z.
There have also been unconfirmed images of Russians making the Z out of captured badges of killed Ukrainian soldiersAn unverified picture of terminally ill children from hospice and their parents making a Z formation in Kezan has also circulated around social media.
This has all led to the Z becoming a patriotic symbol for many Russians who want to show their support for the war and Vladimir Putin.
Merchandise featuring the symbol has been sold by Russia Today, who announced it just days into the invasion.
Flashmobs of pro-government supporters have also used the symbol.
It was also used at a pro-war rally in Serbia.
It has also been co-opted as a symbol of far-right nationalism in Russia, a group that has flourished under Putin.
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