почка

Per Bulgarian Etymological Dictionary (it splits the term into two separate lemmas), perhaps:

• From Proto-Slavic *potъčьka, equivalent to потъка (potǎka, “to weave up, to entwine”) +‎ -ка (-ka);
• From Proto-Slavic *počьka, equivalent to *počьkati (“to thrust, to shove”) +‎ *-a (cf. dial. Russian почка́ть (počkátʹ, “to kick up”)).

• IPA^(key):

по́чка • (póčka) f (dialectal)

1. boundary between slots of land (usually in the form of an embankment or a hedge)
2. (Torlak dialects) edge, brink

• заста́ва (zastáva, “frontier”)
• прегра́да (pregráda, “barrier”)
• межда́ (meždá, “boundary”)
• гра́ница (gránica, “border”)
• разде́л (razdél), преде́л (predél, “limit, demarcation”)
• кро́ма (króma, “restriction, bound”) (dialectal)

• “почка”, in Речник на българския език [Dictionary of the Bulgarian Language] (in Bulgarian), Sofia: Bulgarian Academy of Sciences, 2014
• Nayden Gerov, Тодор Панчев (1901) “по́чка”, in Рѣчникъ на Блъгарскꙑй язꙑкъ. Съ тлъкувание рѣчи-тꙑ на Блъгарскꙑ и на Русскꙑ. [Dictionary of the Bulgarian language]‎ (in Bulgarian), volume 4, Plovdiv: Дружествена печꙗтница "Съгласие.", page 249
• Duridanov, I. V., Racheva, M., Todorov, T. A., editors (1996), “почка”, in Български етимологичен речник [Bulgarian Etymological Dictionary] (in Bulgarian), volume 5 (падѐж – пỳска), Sofia: Prof. Marin Drinov Pubg. House, →ISBN, page 568

• IPA^(key):

• Audio:

  (file)

From Old East Slavic почька (počĭka). Vasmer suggests derivation from печь (pečʹ, “bake”); compare пе́чень (péčenʹ, “liver”).

по́чка • (póčka) f inan (genitive по́чки, nominative plural по́чки, genitive plural по́чек)

1. kidney

• по́здно пить боржо́ми, когда́ по́чки отказа́ли (pózdno pitʹ boržómi, kogdá póčki otkazáli)

• → Armenian: պոչկա (počʻka)
• → Ingrian: pocka

Inherited from Old East Slavic почька (počĭka), from Proto-Slavic *pъťьka. Compare Ukrainian по́чки (póčky), Polish pestka, Czech pecka, Slovene реčkà.

по́чка • (póčka) f inan (genitive по́чки, nominative plural по́чки, genitive plural по́чек)

1. bud

• → Ingrian: pocka

• почка in Большой толковый словарь, editor-in-chief С. А. Кузнецов – hosted at gramota.ru