The verbal root sem-, which Holger Pedersen connects with Lith. semiù ‘I draw, empty out’, forms many compounds in Irish by prefixing one or more preverbs. With two such preverbs, for example, this root occurs in to-ess-sem- and to-uss-sem-, the deuterotonic and prototonic pres. ind. 3d sg. of which would be do-eisim, ·teisim ‘pours out’ and do·uisim, ·tuisim ‘brings forth’. Parallel to the latter, one consequently expects fo·uisim, ·fuisim to be composed of the same root sem- preceded by the preverbs fo and uss (oss). Apart from the difference in the initial element, these two verbs are, therefore, structurally identical in other respects.