Koniková dírka (f)
2nd pipe/tube of a triple chanter
The actual semidrone; NB: "Dírka" is a dialect form of "dierka", which is the diminutive of "diera", which translates as "hole" and "bore"; Elschek dubiously "explains" the term, however, as "the tube put in a horsehead", possibly in an attempt to evade the naughty pun referring to the fact that the thumbhole in this semidrone is, as a matter of course, located at the back of the chanter (the stock of which is usually carved in the shape of a horse’s head).
Elschek, Oskár: Die Volksmusikinstrumente der Tschechoslowakei, 2 (Handbuch der europ. Volksmusikinstr. 1/2;2 [Slowakei]). Leipzig, 1983, p.226.