Charting Glossary — Market Data Terms Defined

Market data

OHLC — Open, High, Low, Close: the four prices summarising all trading in one interval.

OHLCV — OHLC plus Volume.

Open — The price of the first trade in an interval.

High / Low — The highest and lowest trade prices in the interval.

Close — The price of the last trade in the interval. On an unfinished interval, the last trade so far.

Candle — One interval's OHLC record, and its visual representation.

Interval / timeframe — The length of time each candle summarises. CoinDock supports 1m, 5m, 15m, 30m, 1h, 4h, 1d, 1w.

Trade count (trades_count) — How many individual trades produced a candle. The field that distinguishes a candle built from 3,000 trades from an identical-looking one built from four. Most interfaces do not show it.

Closed flag (is_closed) — Whether the interval has finished. An unclosed candle is still changing and its shape can invert before the interval ends.

Tick — A single trade, the raw unit candles are aggregated from.

Carried-forward candle — A flat, zero-volume candle some venues emit for an interval with no trades. Looks like price stability; means an absence of trading.

Candle anatomy

Body — The open-to-close range. Long body: decisive movement. Short body: ended near where it started.

Wick (shadow) — The line beyond the body reaching to the high or low. Shows where price went and did not hold.

Body ratio — |close − open| / (high − low). Near 1 means decisive; near 0 means a lot was rejected.

Doji — A candle with almost no body. Conventionally read as indecision; on a thin market often just two trades at similar prices.

Hammer — Small body with a long lower wick.

Shooting star — Small body with a long upper wick.

Marubozu — Long body with almost no wicks.

Engulfing — A candle whose body fully covers the previous one.

Heikin-Ashi — A candle variant computed from averaged values. Smoother-looking, and does not show actual traded prices.

OHLC bar — A vertical line spanning high to low, with a left tick for the open and a right tick for the close. Same four prices as a candlestick.

Volume

Volume — Total quantity traded over a period. Backward-looking.

Base volume (volume_base) — Volume measured in the base asset. Comparable for one pair over time.

Quote volume (volume_quote) — Volume measured in the quote asset. Comparable across pairs, sharing a denomination.

Wash trading — Trading with oneself to manufacture volume without transferring risk. Cheap, common, and why volume is the least trustworthy market metric.

Aggressor side — Whether a trade executed against the bid or the ask. What people usually mean by "buy volume versus sell volume" — which as literally stated cannot differ, since every trade has both sides in equal quantity.

Analysis

Support — A price area where buying has repeatedly stopped a decline. A description of past behaviour, not a force.

Resistance — The same, for selling stopping an advance.

Zone — A band rather than a line. The honest way to mark a level, since price does not respect single ticks.

Trendline — A line drawn through reaction points. Any two points define one, which is why two-point trendlines are not evidence.

Indicator — A transformation of price and volume data. Adds no information — it re-presents what is already there — but does add consistency.

Moving average — The average close over the last N intervals. Necessarily lags, because averaging is what it does.

RSI — A ratio of average recent gains to average recent losses, scaled 0–100. Measures the character of recent movement, not whether an asset is objectively cheap.

Overbought / oversold — Labels for regions of an indicator's scale. An asset can remain in either for a long time; a persistent extreme is information about a trend, not automatically a signal against it.

Pitfalls

Look-ahead bias — Using information not available at the decision point. Reading unclosed candles is the most common instance.

Overfitting — Tuning parameters until historical results look good. A rule that works at 14 periods and fails at 13 and 15 has fitted noise.

Survivorship bias — Analysing only assets that still exist. Severe in crypto, where a large share of tokens have been delisted or abandoned.

Researcher degrees of freedom — The number of choices available to an analyst — levels, timeframes, tolerances. With enough, something always appears to work.

Cherry-picking timeframes — Searching intervals until a pattern appears. Eight re-aggregations of noisy data will produce recognisable shapes by chance.

Out-of-sample testing — Reserving data before starting and not looking at it until a rule is final. Testing on data you have already explored is not testing.

Related

• OHLC Charts Explained
• Candlestick Chart Guide
• Market History Guide