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reckoner

American  
[rek-uh-ner] / ˈrɛk ə nər /

noun

  1. a person who reckons.

  2. Also called ready reckoner.  a collection of mathematical and other tables for ready calculation.

reckoner British  
/ ˈrɛkənə /

noun

  1. any of various devices or tables used to facilitate reckoning, esp a ready reckoner

"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

Etymology

Origin of reckoner

Middle English word dating back to 1175–1225; reckon, -er 1

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.