interaction [interactions](situation or occurrence in which two or more objects or events act upon one another) noun [UK: ˌɪn.tə.ˈræk.ʃn̩] [US: ˌɪn.tə.ˈræk.ʃn̩]Social interaction is the very foundation of social life. = La interacción social es el fundamento mismo de la vida social.
fundamental interaction(basic forces that act between elementary particles) noun [UK: ˌfʌn.də.ˈmen.tl̩ ˌɪn.tə.ˈræk.ʃn̩] [US: ˌfʌn.də.ˈmen.tl̩ ˌɪn.tə.ˈræk.ʃn̩]