Refers to something that can be defined.
La definición de lo que es el arte es difícil de establecer, ya que es un concepto bastante subjetivo.
The definition of what art is difficult to establish, since it is a rather subjective concept.
Un concepto es definible solo si puede ser explicado de manera clara y precisa a cualquier persona.
A concept is definable only if it can be explained clearly and precisely to anyone.