Bar
On a chart, a bar is one period drawn as a vertical line from the low to the high, with a tick for the open on the left and a tick for the close on the right.
A bar and a candlestick show exactly the same four prices (OHLC); only the drawing differs. Traders also use “bar” for any single period, whatever the chart: “the 15-minute bar” is the candle of that 15 minutes.
Learn more: price charts explained and bars vs candles.