1.
gold (metal)
The precious yellow metal.
2.
gold (color)
The color of gold.
3.
Friday
Abbreviation for 金曜日.
金 has three main uses: the metal gold, the color gold, and as an abbreviation for Friday.
AS METAL:
- 金メダル (gold medal)
- 純金 (pure gold)
- 金貨 (gold coin)
- 金塊 (gold bar/ingot)
AS COLOR:
- 金色 (gold color, golden)
- 金髪 (blond hair)
AS DAY ABBREVIATION:
金 = 金曜日 (Friday). Used in schedules: 月水金 (Mon/Wed/Fri).
RELATED METALS:
- 銀 (silver)
- 銅 (copper/bronze)
DIFFERENT READINGS OF 金:
- 金: money
- 金: gold (metal)
- お金: money (polite)
The kanji is the same but the reading determines the meaning.