-ar 1
var. of the adjective-forming suffix -al 1 , joined to words in which an l precedes the suffix: circular; lunar; singular.
[ -aris; r. ME -er -aris ]
-ar 2
var. of -er 2 , often under the influence of a spelling with -ar- in a cognate Latin noun: burglar; cellar; collar; mortar; poplar; scholar; vicar; vinegar.
-ar 3
var. of -er 1 on the model of -ar 2 , used in the formation of nouns of agency: liar; beggar.