What is Hospitality?

Hospitality is the relationship between a guest and a host, or the act or practice of being hospitable. that is, the reception and entertainment of guests, visitors, or strangers, with liberality and goodwill. Hospitality frequently refers to the hospitality industry, which includes hotels, restaurants, casinos, catering, resorts, membership clubs, conventions, attractions, special events, and other services for travelers and tourists.
Hospitality is also known as the act of generously providing care and kindness to whoever is in need.The word hospitality derives from the Latin hospes, which is formed from hostis, which originally meant a 'stranger' and came to take on the meaning of the enemy or 'hostile stranger' (cristal-hostilis) + pets (polis, poles, potentia) to have power. The meaning of "host" can be literally read as "lord of strangers."[1] Furthermore, the word hostire means equilize/compensate.
In the Homeric ages, hospitality was under the protection of Zeus, the chief deity of the Greek pantheon. Zeus was also attributed with the title 'Xenios Zeus' ('xenos' means stranger), emphasizing the fact that hospitality was of the utmost importance. A stranger passing outside a Greek house could be invited inside the house by the family. The host washed the stranger's feet, offered him/her food and wine, and only after he/she was comfortable could be asked to tell his/her name.

The Greek concept of sacred hospitality is illustrated in the story of Telemachus and Nestor. When Telemachus arrived to visit Nestor, Nestor was unaware that his guest was the son of his old comrade Odysseus. Nonetheless, Nestor welcomes Telemachus and his party lavishly, thus demonstrating the relationship between hostis, "stranger," and hostire, "equalize," and how the two combine in the concept of hospitality.
Later, one of Nestor's sons slept on a bed close by Telemachus to take care that he should not suffer any harm. Nestor also put a chariot and horses at Telemachus' disposal so that he could travel the land route from Pylos to Sparta rapidly, and set his son Pisistratus as the charioteer. These illustrate the two other elements of ancient Greek hospitality, protection and guidance.
Based on the story above and its current meaning, hospitality is about compensating/equalizing a stranger to the host, making him feel protected and taken care of, and at the end of his hosting, guiding him to his next destination.
A good definition for children would be: having "you-know-who" over AND sharing all your stuff with them AND smiling.