I don't understand why I couldn't find any questions relating to this, but only questions asking about the meaning of the songs lyrics. I know what Bohemia is, I know what a Rhapsody is, but I don't understand what the meaning is.
"Bohemian" in the title doesn't refer to the region in the Czech Republic, but rather to what is known as the the bohemian lifestyle.
Bohemianism is the practice of an unconventional lifestyle, often in the company of like-minded people and with few permanent ties. It involves musical, artistic, literary, or spiritual pursuits. In this context, Bohemians may or may not be wanderers, adventurers, or vagabonds. (Wikipedia)
A rhapsody is a free instrumental composition played in one extended movement, typically exuberant or full of pathos. So this fits the form of the song well. One of the best known examples is Franz Liszt's "Hungarian Rhapsody" no.2 in C-sharp-minor (he wrote nineteen of them, but this is by far the most famous), and the band chose this title for a DVD released in 2012 containing some of their live performances in Eastern Europe.
The lyrics and the title are deliberatly obscure. Guitarist Brian May said in an interview:
What is Bohemian Rhapsody about? Well, I don’t think we’ll ever know. And if I knew I probably wouldn’t want to tell you anyway, because I certainly don’t tell people what my songs are about. I find that it destroys them in a way, because the great thing about a great song is that you relate it to your own personal experiences in your own life. I think that Freddie was certainly battling with problems in his personal life, which he might have decided to put [a lot of himself] into the song himself. He was certainly looking at re-creating himself. But I don’t think at that point in time it was the best thing to do so he actually decided to do it later. I think it’s best to leave it with a question mark in the air.”
Freddie Mercury also said:
‘Bohemian Rhapsody’ didn’t just come out of thin air. I did a bit of research, although it was tongue-in-cheek and it was a mock opera. Why not?
I think people should just listen to it, think about it, and then make up their own minds as to what it says to them.
In her book "Queering the Popular Pitch" (Routledge, 2006) music scholar Sheila Whiteley suggests that:
the title draws strongly on contemporary rock ideology, the individualism of the bohemian artists' world, with rhapsody affirming the romantic ideals of art rock.
In her book "Listening to the Sirens: Musical Technologies of Queer Identity from Homer to Hedwig" (University of California Press, 2005) author Judith Peraino says:
Mercury intended ... [this song] to be a 'mock opera', something outside the norm of rock songs, and it does follow a certain operatic logic: choruses of multi-tracked voices alternate with aria-like solos, the emotions are excessive, the plot confusing."
But now Freddie's dead so we're never going to really know for certain what he meant.