apothem

[ap-uh-them]

noun Geometry.

a perpendicular from the center of a regular polygon to one of its sides.

Origin of apothem

1855–60; < French apothème, probably on the model of Greek hypóthēma base; see apo-, theme

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Examples from the Web for apothem

Historical Examples of apothem

The "Apothem is a perpendicular from the vertex of a pyramid on a side of the base."
The Solution of the Pyramid Problem
Robert Ballard
In any pyramid, the apothem is to half the base as the area of the four sides is to the area of the base.
The Solution of the Pyramid Problem
Robert Ballard
A peculiarity of this pyramid is, that base is to altitude as apothem is to half base.
The Solution of the Pyramid Problem
Robert Ballard
I have mentioned the above to show how very nearly these ratios agree with my exact ratio of 21 to 34 half base to apothem.
The Solution of the Pyramid Problem
Robert Ballard

British Dictionary definitions for apothem

apothem

noun

the perpendicular line or distance from the centre of a regular polygon to any of its sides

Word Origin for apothem

C20: from apo- + Greek thema, from tithenai to place

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012