Putting my Oxford English Dictionary uni-based subscription to mis-use I looked up the term Sidekick
SIDEKICK:
1. A companion or close associate; spec. an accomplice or partner in crime; a subordinate member of a pair or group. More loosely, a friend, a colleague.
3. An incidental criticism; a passing or indirect attack, a ‘side-swipe’
This whole thing began with a debate on the DC Comics Supergirl messageboard brought about by the new solicitation of Superman/Batman
SUPERMAN/BATMAN #62
Written by Michael Green & Mike Johnson
Art and cover by Rafael Albuquerque
When the inmates take over Arkham Asylum, it's a job for the World's Finest duo – Robin and Supergirl! Rafael Albuquerque (BLUE BEETLE) joins the series as regular artist for a story we could only call "Sidekicked!"
As we all know the first superhero sidekick in the form was Robin, the Boy Wonder. Introduced in 1940 after just a year of Batman's first publication. It was this partnership that made Batman famous yet certain 'fans' consider Robin an embarrassment. Famously director Christopher Nolan refuses to add Robin to his movie interpretations. Being a sidekick is treated as embarrassing, yet Robin is more famous that 99% of the DC Universe. He is an icon, part of the World's Finest and founder of the Teen Titans. Yet the modern equivalent of World's finest excludes the character in favour of Superman/Batman. The five seasons of animated series Teen Titans shows that the character is still speaking to young boys and girls, is still cool and is still incredibly important. All this said he gets less respect than Aquaman. Why?
The tragedy of the sidekick is that they can never become the master. Comics are a static form, Batman will not stay dead for long, Superman never stayed dead for long and Wonder Woman is never far away. Creators constantly have the Legion from 1000 years in the future fanboy these 3 characters as 'the best'. How depressing is that? In 1000 years it never gets better than this. The next generation is in a constant state of subordination. Dick Grayson of course graduated to Nightwing yet was never considered equal to Bruce. He may soon become Batman..again. Which will be incredibly intresting as to how much respect he gets in the DCU as a whole compared to Bruce. It should also be interesting to see how Wally is treated now his mentor has returned from the dead.
But as will all popular characters, they can't be kept down. With Tim Drake's Robin a self titled comic was created and not long after one for his predecessor Nightwing. They were successful for 12-14 years detailing the duos soli adventures. This is where out OED definition stumbles. Tim and Dick were not sidekicks in these volumes. During the period these were published the focus in Batman was more on his struggles and the duo was put aside. I haven't counted but I would bet Tim Drake has more solo adventures than team ups with the Dark Knight. Of course we can't forget the Teen Titans, founded by Robin and 'sidekicks' in the Silver Age. While the boys of the group were tagalongs of the older heroes Wonder Girl was a new creation. She was created when the writer confused a tale of Diana as a young Wonder Girl rather than Wonder Woman as a separate character. (Its interesting to note that Supergirl was excluded despite seeming like an obvious choice in the 60's) Here the sidekicks could have their own adventures but by having their own adventures separate from their mentor they become less of a sidekick and more independant heroes. After all, the definition requires the duo to be together.
Of course the definition is flawed. Lets break it down into its parts
A companion or close associate
an accomplice or partner in crime
a subordinate member of a pair or group
More loosely, a friend, a colleague
and lets apply it to other characters
Commisioner Gordon, A companion or close associate of the Batman- for sure, A partner in crime- does partner against crime count, Batman depends on Gordon's role in the Gotham Police and so the Commish is therefore an accomplace to the Batman's actions, a subordinate- in what way? Batman is more skilled and more famous.
Mon-El- a companion or close associate of Superman- of course, he is 'Superman's Big Brother', an accomplice or partner in crime- in the legion and in the modern day, a subordinate member- while he is as powerful as superman he lacks experience and knowledge of modern life.
Both characters I think we'd agree aren't sidekicks. By this loose definiton Batman is Superman's sidekick in Superman/Batman. Its time to make our own definition based on
-amount of time spent as a team, all characters work together, some more frequently than others
-role of the 'subordinate' character. There are many ways to be subordinate both in-universe and based on hype/popularity.