- -th-th1-th[ME -th, -the < OE -thu, -tho, -th, akin to Goth -itha (< IE * -ita > L -ta, Sans -tā): in words such as height, sleight, the -th has become -t] suffix forming nouns1. the act of ____ing [growth]2. the state or quality of being or having [wealth, depth]-th2-th, -eth[ME -the < OE -tha, -the, -otha, -othe < IE * -tos > Gr -tos, L -tus; in fifth, sixth, eleventh, twelfth, it replaced the orig. OE -ta, -te] suffixforming ordinal numerals [fourth, ninth]: Also, after a vowel, -eth-th3-th[ME < OE: see -ETH2] suffix-ETH2
English World dictionary. V. Neufeldt. 2014.