Everything there is, considered as one. Also the particular sphere a being actually lives in, which is much smaller.
Old English weorold (world), a compound of wer (man) + ald (age, era) — literally "age of man"; the word named human existence and its span before it widened to mean the whole of the physical world.
Two scales share one name here: the whole of everything there is, and the far smaller reach that a given life actually occupies day to day. A house counts as one such reach among the several a person keeps at once.