Proto-Indo-European Roots

Root/Stem: *sú-
Meanings:  to give birth
Cognates (44):
Hellenic Greek uhios, Doric huos (son) (< *sú-)
Celtic Common Celtic *sut- (to give birth), >
Old Irish suth (birth, offspring)
Indic Sanskrit súté, sauti (gives birth), súnu- (son)
Dardic & Nuristani
Iranian Avestan hunámi (I give birth), hunu- (son)
Tocharian Tocharian A se, Tocharian B soyä (son)
Armenian ustr (son)
Balkan Thracian sukis, sukus (girl, boy, juvenile)
Germanic Common Germanic *sunuz (son), >
Gothic sunus, Old English & Old High German sunu, Old Scandinavian sunR (son);
Old English suhterga (uncle, nephew) - another suffix
Baltic Common Baltic *súnus >
Lithuanian & Sudovian súnus, Old Prussian súnus
Slavic Common Slavic *synü (son) >
Russian syn, Ukrainian sin, Belorussian syn, Slovene & Serbo-Croatian & Bulgarian sin, Czech & Slovak & Polish & Sorbian syn
Notes: This one has nothing in common with relative r-stems discussed in our previous issues. This stem denoted the general term of birth in Indo-European, that is why adding different suffixes produced different meanings. The most widespread suffix was *-nu- which exists in the majority of branches and therefore though to be Common Indo-European. Practically everywhere this suffix gave a noun belonging to u-stems.
The one which seems most interesting is Old English suhterga, which was evidently formed by analogy with dohtor 'daughter'.