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definitions

-atory

  1. a combination of -ate1 and -ory1 or -ory2, used infrequently as an independent suffix with the same senses as -ory1 and -ory2: affirmatory; observatory.

Origin of -atory

< Latin -ātōrius, -a, -um, orig. the termination of adjectives formed with -tōrius (see -tory1, -tory2) and verbs whose stems ended in -ā-; reanalyzed in English in the same way as -ator
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for -atory

-atory

suffix forming adjectives
  1. of, relating to, characterized by, or serving tocirculatory; exploratory; migratory; explanatory

Word Origin for -atory

from Latin -ātōrius; see -ate 1, -ory ²
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