The word "xenial" comes from the Ancient Greek word xenia, meaning "hospitality", and the related word xenios, meaning "guest" or "stranger".  It describes something related to the friendly and hospitable relationship between a host and a guest, particularly as it was practiced in ancient Greece. The English suffix "-al" is added to the Greek root to form the adjective. 

According to the Oxford English Dictionary (OED), he earliest evidence for the word "xenial" is from 1858, used in the writings of William Gladstone.  Other sources suggest the word was first used in the late 1700s (1790s) or as early as 1834.

Examples of "xenial" used in a sentence: 
"During the festival, the xenial residents opened their homes to visitors from all over the country." 
"Her xenial nature made her popular among travelers who appreciated her generous welcome."   
"The Fenix tournament's name was an acronym for its core values: friendly, European, non-professional, innovative, and xenial."  
"A xenial approach to hospitality can leave a lasting impression on guests."  
"The community's xenial nature made it a great place for newcomers to meet people." 

Just the facts:

XENIAL Definition & Meaning - Merriam-Webster

xenial Related Words - Merriam-Webster

XENIAL in Thesaurus: All Synonyms & Antonyms