What constitutes a Lucid Dream?

What constitutes a Lucid Dream? If the end is lucid for a very short time, does that mean you had a LD? Does the whole dream have to be Lucid?

Most people suddenly realize it's a dream when they are starting to wake up. This is because your mind is now getting two seperate sources of input and it immediately realizes which one is real and which isn't. Sorry, that wasn't a lucid dream, it was another phemonon, keep trying though.

I spend so much time trying to get out of it,I know its def a dream all the way through it.
It just feels a certain way that cannot be mistaken with anything else.