Ecclesiastes is a book of the Bible's Old Testament. The title comes from the Hebrew word: Qoholeth (pronounced Koholet).

The root word for Qoholeth: Qahal, is ‘the assembly’ – ‘the congregation’. The Qoheleth is literally one who addresses that assembly. The title of the book in our English comes from the Septuagint of Qoholeth, which is Εκκλησιαστής. The meaning remains the same generally - speaker to the assembly/preacher. It has its origins in the Greek word Εκκλησία (Church). The title of the book is taken from the first verse. The word Qoholeth has found several translations into English; the most widely accepted one being ‘The Preacher’ (after Jerome). Other modern translations (i.e. NCV) have been known to accept ‘Teacher’ as a more appropriate translation.

The traditional view of the authorship of this book attributes it to Solomon. However, modern scholars generally believe that it dates from the later period of the Babylonian captivity. The writer represents himself implicitly as Solomon (1:12), though alternate interpretations are also possible.

It has been styled The Confession of King Solomon. The keynote of the book is sounded in ch. 1:2, KJV:

"Vanity of vanities! saith the Preacher,
Vanity of vanities! all is vanity!"

i.e., all man's efforts to find happiness apart from God are without result.

See also Bible, Tanakh.

Initial text from Easton's Bible Dictionary, 1897 -- Slightly updated but this is a complex text, and the above is a very simplistic reading.