Wordcount stands for the number of words you have in your novel. Many young NaNoers (8-10, sometimes a little older) will go for a small wordcount. In the adult NaNoWriMo you have to get at least 50,000 words.
On the YWP and Camp NaNoWriMo, you can set your wordcount goal. On the adult NaNoWriMo, it is fixed at 50,000 words, but you can always surpass your goal.