A group is defined as three or more individuals who interact over time, depend on each other, and follow shared rules to achieve a common goal. An ideal group consists of 5-7 people united by a common goal. Groups form to satisfy social needs, solve problems, share knowledge, feel secure, and boost self-concept. Factors like cohesion, size, power relationships, interaction patterns, and norms affect group communication. Effective groups have collaborative relationships, clear purpose, creative thinking, focused efforts, and open communication with conflict resolution.