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-ial

American  
  1. variant of -al.

    gubernatorial.


-ial British  

suffix

  1. of; relating to; connected with

    managerial

"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 -ial

Extracted from Latin loanwords in which -ālis (adjective suffix) is joined to stems ending in i; -al 1. filial, imperial 1