Is there a linguistic term for words which are semantically meaningless in English? For example, suppose we have the sentence:
Although he already has a car, he bought a new one.
Here, although would be a semantically meaningless word (doesn't really contain any information at all).
Also, are there any books/papers with a lexicon of such words?
EDIT:
As some people in the comments pointed out although is not meaningless: it informs you that the speaker did not expect the subject to buy a new car.
What I am trying to say is that I am looking for some class of words that contain so little information that if you drop them in a sentence, the sentence will not lose its meaning (or at least the amount of losing information is almost zero).
For example, the phrase he already has a car informs us that the subject has a car, and the phrase he bought a new one informs us that the subject bought a new one.
The word although contains almost no information and if we drop it, the sentence will barely lose meaning. But if we drop any other word (except for the determiners "a"), the sentence will lose meaning.