Final answer:
Referring to individuals' physical posture during a conversation is simply called 'posture,' which is a part of body language significant in communication.
Step-by-step explanation:
The term referring to individuals' physical posture during conversation is simply called posture. Posture is the position of the body and is an integral part of body language that can affect how a message is received during communication. When delivering a speech, having an upright and relaxed posture is crucial as it signifies confidence and engagement with the audience. Movements should be controlled and purposeful, coinciding with key points of the speech to maintain the attention of the audience. It's also vital to be culturally aware as different cultures may interpret postural cues differently.
Quintilian's advice from 'Institutes of Oratory' suggests that an orator's physical presence, from the poise of their chest to the positioning of their feet, plays a significant role in the delivery of their speech. He stresses the importance of controlled, modest movements that complement the content of the oration. When conversing or presenting, one has to be mindful of nonverbal cues including eye contact and body positioning, as these can be as expressive as verbal communication.