IchimuhanA pip is the standard unit of price movement in forex - on EUR/USD, one pip is a move of 0.0001. If the price goes from 1.1625 to 1.1626, that's one pip. It's the unit behind every number on a published plan: an entry, a target, a stop, and the result on a closed trade are all just pip distances from each other.
Why the fourth decimal, not the second or the fifth
Most currency pairs, EUR/USD included, are quoted to four decimal places, and the pip sits at that fourth digit. That's a convention, not a law of nature - pairs involving the Japanese yen are quoted to two decimals instead, so a pip there is a move of 0.01, not 0.0001. It's worth knowing that difference exists, even on a desk that only publishes EUR/USD, because it's the thing that trips people up moving between pairs.
Real EUR/USD quotes, including every level published here, actually run a fifth decimal - 1.16250, not 1.1625. That last digit is a pipette, a tenth of a pip, and it's there for precision on the spread and the entry price, not because it changes how a pip itself is measured or counted.
Why it's the unit that matters, not the price itself
A price level on its own says nothing about size. "1.1625" means nothing until you know what it's a pip distance from. A result of +17 pips only means something once it's read against the stop that was risked to get there, and a stop loss only does its job when it's set a real pip distance from the entry, not an arbitrary round number.
A pip is the ruler, not the room - it's how every distance on a trade plan gets measured, never the thing being measured.
That's also the whole reason how many pips EUR/USD actually moves in an average day is worth knowing before sizing anything: a 10-pip stop and a 40-pip stop aren't "tight" or "wide" in the abstract, they're tight or wide relative to how far the pair typically moves - and that's a pip question before it's anything else.