What does "it" mean?

Additional senses

1. 2.As a demonstrative, especially at the beginning of a sentence, pointing to that which is about to be stated, named, or mentioned, or referring to that which apparent or well known; as, I saw it was John. It is I; be not afraid. Matt. xiv.
2. 3.Peter heard that it was the Lord. John xxi.
3. 4.Often, in such cases, as a substitute for a sentence or clause; as, it is thought he will come; it is wrong to do this.
4. 5.As an indefinite nominative for a impersonal verb; as, it snows; it rains.
5. 6.As a substitute for such general terms as, the state of affairs, the condition of things, and the like; as, how is it with the sick man Think on me when it shall be well with thee. Gen. xl.
6. 7.5. As an indefinite object after some intransitive verbs, or after a substantive used humorously as a verb; as, to foot it (i. e., to walk). The Lacedemonians, at the Straits of Thermopylæ, when their arms failed them, fought it out with nails and teeth. Dryden. Whether the charmer sinner it, or saint it, If folly grows romantic, I must paint it. Pope. Its self. See Itself.