interpersonal

adj. pertaining to or involving relations between persons

In the contexts of sociology and of popular culture, the concept of interpersonal relationships involves social associations, connections, or affiliations between two or more people. Such persons may  interact overtly, covertly, face-to-face; or may remain effectively unknown to each other (as in a virtual community whose members maintain anonymity and do not socialize outside of a  chat-room).
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Adjective
1. occurring among or involving several people; "interpersonal situations in which speech occurs"
(similar) social

adj. interpersonal, pertaining to or involving relations between persons

= interpersonal [inter-personal], person-to-person.
Ex: New techniques are constantly explored, and a few, like the use of the videocamera, are helpful in emphasizing the necessity of satisfactory interpersonal communication.
Ex: Networks became joined together into larger metanetworks as the advantages of information sharing and person-to-person communication became quickly apparent.
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* conflicto interpersonal = interpersonal conflict.
* espacio interpersonal = personal boundaries.