Where does “that's” come from?
that's (English) comes from English -’s, from Middle English -s, from Old English -es, from Proto-Germanic -as, from Proto-Indo-European -ēs, from Proto-Indo-European -ess, from Proto-Indo-European -os — Creates action nouns or result nouns from verbs;...
that's (English): whose, of which
Ancestry of “that's”, step by step
| Step | Language | Word | Meaning |
|---|
| 1 | English | -’s | — |
| 2 | Middle English | -s | Adverbial genitive ending, developed into the... |
| 3 | Old English | -es | possessive marker, indicating that an object... |
| 4 | Proto-Germanic | -as | — |
| 5 | Proto-Indo-European | -ēs | Primarily forms adjectival bahuvrīhi compounds |
| 6 | Proto-Indo-European | -ess | — |
| 7 | Proto-Indo-European | -os | Creates action nouns or result nouns from verbs;... |