Tell Off Meaning
(military) To divide and practise a regiment or company in the several formations, preparatory to marching to the general parade for field exercises.
Example: To rebuke, to reprimand, or to admonish, often in a harsh, direct way.
To count (members of a sequence), to enumerate.
1903, Field and Stream (page 755)
The Recruit looked thoughtful and told off the days on his fingers.
(Can we find and add a quotation of Farrow to this entry?)