OHLC
OHLC stands for open, high, low and close: the four prices recorded for every period of a chart. The open is the first trade, the high the highest, the low the lowest and the close the last.
Bar charts and candlestick charts both draw all four; a line chart uses only the close. On Bitcoin on 21 September 2026 (daily, Binance) they were: open 81,178, high 87,396, low 80,850, close 86,620. Many data feeds add a fifth number, the volume, and call it OHLCV.
Learn more: price charts explained and what is a candle?.