This brings up an interesting
topic. Before I go into the nitty gritty, I'd like to mention that in
Latin, there is no direct way of saying "
yes" or even "
no." Typically, if one
Roman were talking to another and said "
Are you the farmer who lives in a province of Asia?" the other would respond either "I am..." or "I am not...." Anyway, without further ado, the reason you're -really- reading this node:
Whether "no" is a complete sentence is dependant enirely on the
definition of a sentence. Do me a
favor, friend, head on over to
sentence and scroll down to Webster's entry. Lots of entries, eh? For the
moment, let's skip down to the entry under
grammar.
"A combination of words which is complete as expressing a thought, and in writing is marked at the close by a period, or full point."
Ok, that's interesting. A sentence requires a few things: some words that make sense, and that little dot thing. Okay, but what on earth makes a bunch of words "complete as expressing a thought"? What makes a sentence complete wih respect to expressing a thought? Well, if we scroll down Webster's writeup a teeny bit more, we find he says
"Sentences are simple or compound. A simple sentence consists of one subject and one finite verb; as, "The Lord reigns."
Ahh, so there we are! A
subject and a
verb. Is no a subject and a verb? No. But wait, isn't that a complete sentence? I just expressed a complete thought and put that little dot thing after it! Unfortunately, grammatically speaking, it is not a complete sentence, simply because it lacks a subject and a verb. You did
express a thought, but not by means of a subject and a verb (and a dot).
To refute FordPrefect's saying that "no." as a sentence has an implied verb and subject, I'll say this: In English, we imply subjects all the time (Go to the store. Who? You, go to the store). It's how we use the imperative mood; we are giving a command, and the one whom we are addressing understands that s/he is the implied subject of the command. This is a very special case and we rarely imply subjects outside of the imperative sense. Implying a verb is something we don't do. The word no does not imply a subject and a verb all on its own, grammatically speaking. Of course we understand that, if a mother tells her son to go to his room and the son says no, the son really means "no, I shall not go to my room."; however, because we understand what he means does not mean that the word no implies the subject and verb in a sentence.
The issue here is not so much what "no" means--we all know what it means--but rather, with what a sentence denotes. If this node were titled " 'no is a complete thought' " we wouldn't be having this discussion. A sentence contains a complete thought expressed by a subject, a verb, and a period. No is neither a subject nor a verb; thus, it can not be a complete sentence.