What is another word for is on back?
Pronunciation: [ɪz ˌɒn bˈak] (IPA) 
The phrase "is on back" can be expressed using a variety of synonyms. "Lying supine" is a more formal and clinical term that describes the position of someone lying face up. "Reclining" is a more relaxed term that also refers to someone lying down, but suggests a more comfortable or leisurely pose. "Resting," "relaxing," and "unwinding" all convey a sense of ease or calmness associated with being in a prone position. Finally, "horizontal" and "flat" are more abstract synonyms that simply describe the physical orientation of someone lying on their back. All of these terms convey the same basic idea that someone is lying down with their back against a surface.
