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The term unified model is used in astrophysics for models that combine previous models, often to explain previous observation-based classes or types of some object.
A very common example such unified model in astrophysics is the unified model of AGNs: that a number of observational types of active galactic nuclei consist of a substantial torus-shaped cloud (obscuring torus) with considerable dust surrounds the supermassive black hole (SMBH) and its accretion disk. Material within that inner, partially-hidden region has a high velocity and temperature, leading to the broad lines. These are seen only from some angles. Material further from the SMBH is somewhat heated by the accretion emission, forming the narrower lines that are not blocked from our view by the torus. This explains the fact that observed AGNs generally show the narrow lines (revealing a narrow line region) but only some show the broader lines (revealing a broad line region): we see the latter only when our viewing angle (given our line of sight) is such that we see what is encircled by the torus.