-th1
/θ/(also -eth)
suffix
Forming ordinal and fractional numbers from four onwards: fifth sixty-sixth
Origin
Old English -(o)tha, -(o)the.
-th2
/θ/suffix
Forming nouns:
1(From verbs) denoting an action or process: birth growth
2(From adjectives) denoting a state: filth health width
Origin
Old English -thu, -tho, -th.
-th3
suffix
Variant spelling of -eth2 (as in doth).