
Boiling water is plain water heated to its boiling point — about 100 °C (212 °F) at sea level.
Neutral — no flavour, aroma, sweetness or acidity. It adds only heat and volume.
Freshly boiled water is the base of hot drinks — a Hot Toddy, a grog, a hot buttered rum. It brings the drink to serving temperature, dissolves sugar and honey, and adds volume. Add it straight off the boil so the drink stays hot.
Any freshly boiled drinking water does the job — what matters is the heat and the dilution, not the water. Cold drinks don't use it; there, melting ice or cold water dilutes instead.
Hot water
Boiling water is at a full boil (about 100 °C at sea level). Recipes that say 'hot water' usually mean water that's heated but not boiling.
Water is brought to a full boil; boiling changes its temperature, not the water itself. The boiling point isn't fixed — it drops at altitude and rises when salt or sugar is dissolved in.