The Estonian vanik ’wreath’, Livonian vāńka id. and Finnish vannikko, ­vannikka ’(bride’s) wreath’ has been considered either a Baltic or an older Latvian loanword sharing its root with the Lithuanian vainìkas ’Kranz, Krone, (bei ­Mädchen) Jungfrauenschaft’, Latvian vàinags ’der Kranz, die Mädchenkrone, Kopfschmuck, den die Unverheiratete trägt und der als Zeichen der Jungfräulichkeit gilt; ­jede der über dem Grundbalken liegenden Wandbalkenreihen eines Gebäudes; der Umlauf oder Kranz am Rade’. The above etymology, however, has remained an object of ongoing discussion due to the unusual substitution ai > a. The article analyses the possible Baltic, resp, Latvian origin of two words with hitherto unclear etymology from the South Estonian area, in which the diphthong of the source word is substituted by a monophthong. `posle pl. ’bad or hollow grain removed by winnowing’, cf. Latvian pàišļi ’die Streu’, pl. ’beim Schwingen sich bildende Flachsabfälle’, Lithuanian paĩselis, paĩsas ’removed awn of barley’. It is not clear why the Baltic diphthong ai has been substituted by by a monophthong. `sirduss, also sirdak ’bunch of flax or hemp for rope-making; strand of rope; hank of wool; also: pinch of straw’, cf. Latvian šķiêdra etc. ’Flachsstengel; Flachsfaser, Faser überhaupt’, Lithuanian skiedrà, skiedarà ’Span, Splitter’. The expected South Estonian substitute of the Latvian diphthong ie would be the diphthong ie, which alternates, paradigmatically, with the overlong vowel î.