I'm imagining a colony on Mars, but am finding it distracting to refer to them as 'Martians'. Historically, what determined the names of colonies and colonists, and what would be a good alternative to 'Martians'?
Anything you want.
Since you are imagining the colony, you can give it any name you want. "A Mars colony" is not likely the top pick. What the colonists are called could then be derived from that.
Some alternatives :
Name derived from the location of the first colony.
Name derived from the name for the Mars colonization project. "Apollo" and "Mercury" are project names you might be familiar with.
The name could be derived from the person or movement that was important for the project.
The name could also be derived from the actual people. The colonists might have a charismatic leader. They might have some trait that becomes linked to them in the popular discussion. For an unrealistic example if you need IQ above 120 to be a colonist, any of the popular expressions for smart people would do. Or the name could the derived from the number. "One-twenties" for example. Or if their were 566 original colonists, you could derive the name from that.
By now it should be clear that "anything you want" is a fairly accurate answer.
Historically speaking, colonists where originally named after their country of origin rather than the new colony.
You would have the English colonists in the American colonies.
- So in your case, you would have the Terran colonists in the Martian colonies.
Then it shifted slightly to become more location orientated. The Virginia colonists, or the New England colonists. Not named after the main continent/location but rather after smaller definable groups.
- So in your case, it would the Hellas Basin, Olympus Mons or Private Federation colonies on Mars.
Over time this would then change from English colonists in the Americas to the American colonists. But the 'colonists' was always added. They were never just Americans. They still belonged to the home country and were always described as such.
- So then in your case it becomes, the Martian colonists.
Only after independence from the home world would you really start to have your stated problems.
- Those bloody Martians!
Then you can do what we've done in the past. And still identify them. So Irish-American, African-American, Yankees, Chinese-American etc.
'Americans' is actually a confusing example to use as they named their country after the continent name. For further examples, you don't call Canadians, North Americans. In South America you have Peruvians, Argentineans, Chilians and Brazilians to name a few. South America just describes the larger region they are from but you would rarely need to say "all South Americans decided to ...".
- we have so many Martians, you have the American-Martians, Chinese-Martians, Musk-Martians etc.
By then there are probably enough large identifiable factions that you can just call them by their faction names. Whatever those may be.
Reserve use of the term "Martian" to lump everyone into one anonymous group, when you are referring to large groups of different types of Martians. Could technically have a more negative conatation than you would have, if you would take the 2 secs extra to indentify further who you were talking about.
Rust cloaks (red dust of mars)
Reds (red planet) (or Communists)
Red colour- rouge(fr. But also similar to rogue)
There could be a name that derives from their reputation or function.
Vultures x Settlers
Or you can go with mythology and find names of children of Ares.
Amazons, Thrax, Phobos etc.
Then there is an option to name them after a first colonisation ship or a first martian settlement. So you can name them anything you fancy.