Now archaic, yester was an adjective to describe a time period in the past. Today it has been absorbed into the word yesterday, and is seen sometimes in the word yesteryear. Its other forms (yester-week, yester-hour, yester-month) have become so antiquated they are not listed in the dictionary. However, now and then they do appear in text, usually with a connotation of humor or acknowledgement of their age. Usage seems to suggest that most consider these compound nouns which deserve a hyphen. This method reminds readers of the meaning of yester- as a prefix.
Note that the term yesteryear is listed in the dictionary and is spelled as one word without a hyphen.
Side note: In terms of spelling, yesterday has an ‘e’, while Saturday (named for the god Saturn) is with a ‘u’.
Examples:
Tens of thousands of people marched through Hong Kong yesterday in support of China and to protest Occupy Central, a pro-democracy movement that says it will plan to stage a civil disobedience sit-in unless the Chinese government allows the Hong Kong public to nominate and vote for its next leader. [CNN]
Popular yesteryear actor Amala Akkineni is making a comeback in Tamil, but not to the big screen. [The Hindu]
What are some of your memories of Coast restaurants of yesteryear? [Sun Herald]
Early in their win over Houston, the Giants were looking like the Jets of yesteryear, or even yester-week. [Wall Street Journal]
9:Â Number of game-winning field goals in Dan Bailey’s career, after yester-afternoon’s OT upright-splitter. [SB Nation]