Ego vs. Personality
Words are used in different ways in different traditions, and sometimes even within each tradition. Here is one way of defining some central words that I find useful.
Small Mind
Small mind refers to local awareness exclusively identified with the organism, with the particular body and habitual patterns on physical, emotional and mental levels. There is a dualistic view, seeing the organism as "me" and everything else as "other".
There is a sense of separation between the inner and the outer world. And from this, a sense of precariousness, of being the victim of circumstances. And there is a blind attachment and acting on the processes of the personality, such as likes and dislikes, thoughts and ideas.
Of course, this is a somewhat caricatured picture, but the overall characteristics are there.
When awareness is local and exclusively identified with the organism, there is "ego". Ego refers to a more blindly dualistic way of operating, of blindly identifying with the organism and the personality, and of a tendency to blindly be caught up in the processes of the personality.
There is little spacious awareness, and little choice in how we relate to the inner and outer world.
Ego is what is there when we operate from small mind, although the term may not be very useful as it is understood in so many ways, and has a charge to it as well for many. Small mind seems sufficient.
Personality
The personality refers to the processes of the organism - physical, emotional and mental. These are just there, as any other phenomena in the inner/outer world. They arise, unfold, fade.
They can be discerned from all other phenomena, and they are part of the same fluid and seamless whole as all phenomena of the inner/outer world.
The personality is in a sense the "software" of the organism. It is what gives preferences, habits and some predictability in how the organism relates to the rest of the world.
And these patterns are formed and conditioned by our biology, culture and personal experiences.
Big Mind
Big mind is when awareness is more awakened. When there is a sense of spacious awareness in which all phenomena of the inner/outer world unfolds.
There is a sense of overview, and of choice in how we relate to the inner/outer world. We are liberated from blindly acting on the processes of the personality.
We can be more responsive to the specific situation, to what the situation calls for.
Summary
In small mind, there is a local awareness blindly attached to and acting on the processes of the personality. There is little choice, and acting on habitual patterns. There is a strong sense of separation between the inner and outer world. There is a resistance to experiences. There is a sense of rigidity and precariousness. And all these form what some call ego.
In Big Mind, there is spacious awareness in which all phenomena of the inner/outer world unfold. There is a sense of overview, choice, and increased responsiveness to the particular situations.
Awareness is centered on an organism and personality, but since there is a more transdual view, there is no ego. And since there is no/little resistance to experiences, awareness is free to more fully engage in life - to be more fully and deeply embodied in the personality and the world.
There is a deepening of transdual awareness, and a deepening of living this awareness in the organism and the world.
There is spacious awareness within which all phenomena unfolds, and they are a fluid and seamless whole. Awareness melts into all phenomena and experiences.