第三醫學 dìsānyīxué rehabilitation medicine Origin Definitions Defs Strokes Stroke Words Sentences Sents 第 dì affix [ordinal] Prefix used before a number or the question word 几 jǐ to form an ordinal number indicating sequence or rank三 sān numeral third the third in a series; ordinal number three医学 醫學 yīxué noun medicine medical science; the study of medicine