Doji
Candle where open ~ close - indecision signal.
Doji = candle with tiny body (open and close almost equal) and often long wicks. Means buyers and sellers had equal strength. After a long green run a doji warns of reversal; same in downtrends. Variants: gravestone (top wick only), dragonfly (bottom wick only).
In plain words
A candle with almost no body - open and close ended at the same place. Buyers and sellers were even.
Example
BTC Mar 13, 2024: D1 doji after 8 green candles in a row, ATH 73k -> next day drop to 68k.