In astrology, the concept of "house 1" refers to the first house in a natal chart, also known as the Ascendant or Rising sign. The first house represents the individual's self-image, personality, physical appearance, and how one presents oneself to the world. It is associated with beginnings, new initiatives, and the way one approaches life. The sign and any planets located in the first house can offer insights into a person's demeanor, behavior, and overall outlook on life. 

The first house in astrology, often referred to as the "House of Self" or the "House of Identity," holds significant importance in shaping an individual's personality, appearance, and overall temperament.

1. First Impression and Persona: The first house represents the initial impression we make on others and how we present ourselves to the world. It signifies our immediate, instinctive reactions and the mask we wear in social interactions. 

2. Physical Appearance and Body: This house governs our physical body, including our facial features and overall appearance. It highlights how we project ourselves physically and how others perceive us based on our looks. 

3. Overall Temperament and Outlook on Life: The first house influences our general temperament and outlook on life. It reflects our basic sensibilities, approach to life, and the manner in which we tackle new opportunities and challenges. 

4. Sense of Self and Identity: At its core, the first house symbolises our self-image, ego, and consciousness. It defines our individuality and represents the essence of who we are as individuals. 

5. Mannerisms and Body Language: This house encompasses our mannerisms, facial expressions, hand gestures, and overall body language, all of which contribute to the impression we leave on others. 

6. Appearance as Self-Expression: The first house also relates to how we express ourselves through our appearance, including the styles and trends we adopt in clothing and grooming. 

In summary, the first house serves as a lens through which our personality, appearance, and identity are viewed and interpreted in astrology. It defines our outward behavior, preferences, and the roles we choose to play in the world. Additionally, it plays a crucial role in shaping our early life experiences and developmental journey.