Of An Meaning

(idiomatic, dialectal) Indicates a more or less habitual activity during the given part of the day.

Example:   The two main players were roughly of an age.
1825 March 16, Robert Southey, “Letter XVII”, in Life and Correspondence of Robert Southey, page 56:
  He and F were of an age and standing, the giants of the house, but F was the braver, and did us the good office of keeping him in order.
1854, Elias Darnell, Journal of the Campaign, page 74:
  Allen said, "If we were of an age, and on an equal footing, you would not give me the lie so often."
2001, Jacqueline Carey, Kushiel's Dart, ISBN 0312872380, page 73:
  When she turned to kiss Alcuin, they were of a height.
  Of an evening, I like to play chess. i.e., On some evenings, I like to play chess.
  Of a morning, they would work in their garden. i.e., They generally worked in their garden in the morning.