Minimum phase
A filter that, for a given magnitude response, has the least possible delay — everything happens after the impulse, nothing before it.
Mathematically, all its zeros sit inside the unit circle. In practice, the energy of the impulse response is packed as early as it can be. Analogue filters, and most IIR filters in a digital EQ, are minimum phase. The catch is that phase shift varies with frequency: a boosted bass arrives fractionally later than the treble.
The opposite camp is linear-phase EQ, which delays every frequency by the same amount but produces a symmetric impulse response that rings before the transient. Which one sounds better is among audio engineering's evergreen arguments. Every magnitude response has exactly one minimum-phase version, and it can be derived from any filter via the cepstrum or a Hilbert transform.