Means to have skills in many different things, yet not to master any one thing.
I tradesman might be considered a master, because he/she has mastered the skills of their trade, in the singular sense. Yet a handyman/woman may be considered a jack of all trade, because whilst they do not possess the intimate mastery of a singular set of skills, they possess a broader strength in a larger amount of skills.
I tradesman might be considered a master, because he/she has mastered the skills of their trade, in the singular sense. Yet a handyman/woman may be considered a jack of all trade, because whilst they do not possess the intimate mastery of a singular set of skills, they possess a broader strength in a larger amount of skills.