Close interaction is a term used to describe a relationship between two or more people or entities that involves frequent and direct CONTACT. It is often characterized by a high level of cooperation, collaboration, and mutual understanding. The two crossword solutions for this term are CONTACT (7 letters) and SYNERGY (7 letters). CONTACT implies a physical or virtual connection between two or more people, while synergy suggests a cooperative effort that results in a greater outcome than the sum of its parts. Together, these two words capture the essence of close interaction, which is a relationship that involves frequent and direct CONTACT, cooperation, collaboration, and mutual understanding.