Candle range
The range of a candle is the distance from its high to its low, wicks included.
Definition
The range of a candle is the distance from its high to its low, wicks included.
A body covers only the open to the close, and the range covers the whole candle. Average range is this figure averaged over a stretch of candles.
Gap size is measured between two candles and not inside one, so it is not a candle range.