Hi i am planning to register a domain with keyword "whatsapp", I am not able to find whether it is trade marked by whatsapp. If anyone knows how to check that, please let me know.
You can own a domain with a trademarked name in it, as long as it is not being used in the field of the TM holders TM, was not registered in "Bad Faith" (meaning you want to profit from the TM holders TM), are not profiting from the TM holders TM in any way (including parking the domain), is a generic name/word as well as a couple other reasons. However, it will be hard to prove that the domain wasn't registered in "Bad Faith" in this case since the TM/Name is more unique than many. As an example, you can have a domain with the name "Apple" in it, even though Apple Inc. has the name TM'd. The domain/site just can't be used to profit in any way from a field that Apple Inc. has their TM in. If you had "HotApple.com" and it was about the fruit, then you would be fine in most cases, but if you used it to sell hot Apple iPods, iPhones, Phone cases, etc., then you would be in violation of the Apple Inc. TM.
I think the whole thing depends on what you're trying to do with that domain. Are you able to give us any more details?