- Meanings and Origins of Phrases
Having suitable skill in multiple things, but not being an expert in any of them.

Example: While playing basketball, Bill was asked what type of shot he was best at. He replied that he's decent at all kinds, long, medium, and even close range shots like layups. Thus, when it comes to shooting the ball, one might say that Bill is a 'jack of all trades, master of none.'​
The word 'jack' was used to refer to the common, ordinary man. Thus, a 'jack of all trades' meant a man who was competant at several different skills. The first half of the phrase—jack of all trades—was in use as early as the early 17th century. For example, a Geffray Minshull wrote a book titled Essayes and characters of a Prison and Prisoners. The book was published in the year 1612, and there's a part from it that reads:

    "Some broken Cittizen, who hath plaid Jack-of-all-trades."

As for the 'master of none' part being added to the expression, the earliest quote of this, from what I've seen, is around the 1800s. For instance, the full version of this saying can be seen in The Atlas newspaper from 1828, where it reads:

    "You rarely meet in England a man who is Jack of all trades and master of none."

Both the long and short version of the expression are still used today.
Note: The origins for most idioms and common phrases cannot be said with a certainty. What's provided are theories that may be plausible to how a phrase originated, but not necessarily so. 

In addition, quotes that contain a particular phrase may be taken from old newspapers, poems, or books that were written centuries ago, but this by no means confirms that the phrase originates from said newspapers, poems, or books. In all likelihood, if an expression is being used in a newspaper, it's probably already a well known saying and is from an older time.
* Whether there's an electrical, plumbing, or some other kind of issue going on with our house, Frank seems to be a jack of all trades because he's been able to fix them all so far.
Know Your Phrase - The Meaning And Origins For Phrases and Idioms  |  J-Letter Sayings

The meaning of the phrase 'jack of all trades, master of none.'
Idioms beginning with the letter - J.
Phrases and Idioms