noun
round gimlet
A hand tool with a spiral tip used for boring holes in wood; a type of auger.
大工さんは円錐で板に穴を開けた。
The carpenter bored a hole in the board with a round gimlet.
錐 is a general term for a gimlet or drill; 円錐 specifically refers to a round gimlet.
Compound of 円 (まる, 'round') + 錐 (きり, 'gimlet'). The reading まるぎり is a straightforward kun'yomi combination.