cir·cum·fix 
(sûrkəm-fĭks′)
(sûrkəm-fĭks′)n.
An affix consisting of a prefix and a suffix, such as the progressive present marker a- ... -ing in dialectal English I'm a-going or the past participle marker y- ... -t in archaic English yclept.
tr.v. cir·cum·fixed, cir·cum·fix·ing, cir·cum·fix·es
To add as a circumfix.