About

1. Around; all round; on every side of.
2. In the immediate neighborhood of; in contiguity or proximity to; near, as to place; by or on (one's person).
3. Over or upon different parts of; through or over in various directions; here and there in; to and fro in; throughout.
4. Near; not far from; -- determining approximately time, size, quantity.
5. In concern with; engaged in; intent on.
6. Concerning; with regard to; on account of; touching.

This use passes into the adverbial sense.
adv.

1. On all sides; around.
2. In circuit; circularly; by a circuitous way; around the outside; as, a mile about, and a third of a mile across.
3. Here and there; around; in one place and another.
4. Nearly; approximately; with close correspondence, in quality, manner, degree, etc.; as, about as cold; about as high; -- also of quantity, number, time.
5. To a reserved position; half round; in the opposite direction; on the opposite tack; as, to face about; to turn one's self about.
To bring about ,
to cause to take place; to accomplish.
To come about ,
to occur; to take place. See under Come.
To go about, To set about ,
to undertake; to arrange; to prepare.
Round about ,
in every direction around.