Wick

The part of a candlestick that is not the body, also called a shadow or a tail. The body spans the opening and closing prices. The upper wick runs from the top of the body to the period's high, the lower wick from the bottom of the body to its low, and the two together with the body span the whole range of the period. A period whose extremes are its own open and close has no wick at all, and a period that travelled a long way and came back has a long one.

What a wick reports is distance that was reached and not held. That is the whole of its content, and the conventional readings built on it, a long lower wick described as buyers turning a level back, a long upper wick as sellers doing the same, and named shapes such as the hammer, are interpretations of that one fact. A period whose open and close are all but identical, a doji, is almost entirely wick, which is why so much is read into it. The wick carries no time and no path. An upper wick can be a single spike lasting a second or an hour spent trading higher before a late return, and the two are drawn identically. It is also entirely a function of the chart's time frame: one wick on an hourly chart is a whole sequence of bars on a one minute chart, where the same episode may not look like a rejection of anything.

The trip is treating the tip of a wick as a price that was available to everyone. Most retail charts are built from one side of the two way price, conventionally the bid, so the printed high is the highest bid and the other side of the market sat a spread away from it throughout. An order that deals on the ask therefore need not have been fillable at the level the wick touches, and two providers whose feeds differ will print slightly different extremes for the same period. The same applies in reverse to a resting order: a wick reaching a level says the market printed there on one side, not that any particular instruction was executed at it.