interact

To act upon each other.

The way staff interact with each other during breaks can play an important role in the workplace.

To act upon each other.

This medication can interact with alcohol, so it's best to avoid drinking while you're taking it.

The fortunes of the master and the servant, intimately interacting, rose together. The Baron’s secret skill had given Leopold his unexceptionable kingdom; and Leopold, in his turn, as time went on, was able to furnish the Baron with more and more keys to more and more back doors.

A short act or piece between others, as in a play; a break between acts.

1912, William Archer, London: Chapman & Hall, Chapter 8, pp. 108-109, […] the flight of time is best indicated by an interact. When the curtain is down, the action on the stage remains, as it were, in suspense. The audience lets its attention revert to the affairs of real life; and it is quite willing, when the mimic world is once more revealed, to suppose that any reasonable space of time has elapsed […]

The play gives detailed descriptions of the instruments used in the interact music […]

Intermediate employment or time.

1750, Philip Stanhope, 4th Earl of Chesterfield, Letters Written […] to His Son, London: P. Dodsley, 10th edition, 1792, Volume 2, Letter 219, p. 344, Play, in good company, is only play, and not gaming; not deep, and consequently not dangerous nor dishonourable. It is only the inter-acts of other amusements.

A pair or series of acts involving more than one person.

Inasmuch as it is impossible to analyze the contents of an entire interpersonal relationship, it is helpful to conceptualize a given communication event as consisting of a series of subevents. Any one subevent may be pulled out as a basic unit for analysis in the study of interpersonal communication; this basic unit may then be called an interact. […] each interact is a distinctive attempt to conceal, repeat, or disclose information and/or to influence the relationship.

As they listened to groups communicate, Fisher and his coworkers noted what each group member said (labeled a speech act) and how the next person responded. This pairing of speech acts is called an interact.