The word Entertaiment is a modern form of entertainment that can take on many forms and scales, from an individual selecting an evening’s entertainment from the now enormous range of pre-recorded products to enjoy alone, to a banquet adapted for two, to a performance intended for thousands. It can also be socially or politically charged, as in a political or religious festival, ceremony, or satire.
The etymology of the word is unclear, but it seems likely that it derives from Latin intertenere, from the prefix inter- meaning “among” or “inside” and tenere, from the Indo-European root *ten- “to stretch.” It took on the sense of entertain guests in late 15c., and that of gratify or amuse in 1620s.
The suffix -ment is an English form of the Latin -mentum (see amazement, betterment, merriment). It is often inserted between verb stems that end in –er (as in commence-e-ment from commencing) or into nouns ending in -ir (as in sent-i-ment from sentir). Also found in such nouns as adornment, embellishment, and engrossment.