1) Incidently or incidentally?
2) Accidently or accidentally?
This Friday Fix is brought to you by my own uncertainty. I have actually avoided using either of these words before because I didn't know the correct spelling and I was too lazy to look them up at the time.
The time has come, my friend.
According to dictionary.com (my fave!), incidentally is the correct form. Interestingly enough, though, both accidently and accidentally are acceptable. Who knew?
Incidentally, the -ally suffix makes perfect sense when you consider that incidental and accidental are adjectives. Slapping on the -ly suffix turns them into adverbs, making the -ally form "most" correct.
Yanno, in case you need a reason. ;-)