conc▪ Probably from *‘best part, choice’, from *‘middle, centre’, from ‘navel’ (↗surraẗ), from ‘navel string’ (↗surr), from WSem (?CSem) *šurr- ‘umbilical cord’, ultimately perh. from a hypothetical Nostr *säR˹U˺ (= *säRo?) ‘sinew, fibre’.
▪ Another etymology is considered by DelOlmoLeteSanmartín2003, where Ar sarar ‘last night of the lunar month’ is seen as cognate to Ug srr ‘to set, sink, hide’, in its turn allegedly cognate to Hbr swr, srr. Tropper2008, however, is not sure about the reading of the underlying Ug phrase b srr špš as ‘at the setting of the Sun’ (as the phrase is rendered in DelOlmoLeteSanmartín2003); he also leaves it open where the vn. srr should be derived from: from sw/yr ‘to leave’ (Hbr √swr) or its »Wurzelvariante« √srr.