Past tense of 'drill': to make a hole using a rotating tool; or to practice something repeatedly until you're good at it.
From Middle Dutch 'drillen' (to bore, rotate). The word entered English in the 17th century and was applied both to mechanical boring and to military/educational repetition.
The military 'drill' (repetitive practice) and the tool 'drill' are historically connected—soldiers were drilled like holes are drilled: creating a permanent mark through repeated force!
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