[1930–35; af(ternoon) + -o, with voicing of -f-; ar is r-less speaker's representation of low back vowel]This word is first recorded in the period 1930–35. Other words that entered Englishat around the same time include: acoustic phonetics, cloverleaf, old school tie, saddle stitch, technical foul-o is a suffix occurring as the final element in informal shortenings of nouns (ammo; combo; condo; limo; promo); -o also forms nouns, usually derogatory, for persons or things exemplifying or associatedwith that specified by the base noun or adjective (cheapo; pinko; sicko; weirdo; wino)