Actually, the word 것 means "thing." This word is given a prefix:
| 이- | this (near to speaker) |
| 저- | that (far from speaker and listener) |
| 그- | that (near to listener), or "that" which was mentioned in a previous sentence |
These prefixes are called determinatives by linguists, because they help you determine where something is in relation to you. You can attach these prefixes to any noun; for example:
| 이책 | this book [here] |
| 저나무 | that tree [over yonder] |
| 그학교 | that school [we were talking about] |