Rule · Chapter 5
cr:5.4.7
A while-static ability is a static ability with a condition that makes it functional under specified circumstances. While-conditional abilities are written in the format “While [CONDITION], [ABILITY]” or “If [CONDITION], while [CONDITION], [ABILITY],” where the ABILITY is the static ability that is functional whenever the CONDITION is met.
Example: Yinti Yanti has the text “While this is defending and you control an aura, it gets +1{d},” which is a while-static ability that is functional when it is a non-permanent defending card because it has a while-condition that is met when the card is defending.