"reckoners" in the noun sense
1. calculator, reckoner, figurer, estimator, computer
an expert at calculation (or at operating calculating machines)
2. reckoner, ready reckoner
a handbook of tables used to facilitate computation
Source: WordNet® (An amazing lexical database of English)
Princeton University "About WordNet®."
WordNet®. Princeton University. 2010.
View WordNet® License