Thread:User talk:CodeCat/PIE *plōtus etymology

I'm sorry for the back and forth about this one. I was working off of the AHD of IE Roots (http://web.archive.org/web/20080627204039/http://www.bartleby.com/61/roots/IE415.html) section I.6. which lists the the lengthened o-grade of *pleu- as *plō(u)- (or *plō(w)-, as the case may be). It seems very convenient of them just to list the u/w as optional, but do you think that this is a fair explanation, particularly if we list it as *plō(w}- + -*tus?