Where does “маслечко” come from?

маслечко (Ukrainian) comes from Russian -ечко, from Ukrainian -це́, from Ukrainian -ко, from Proto-Slavic -ьko.

Ancestry of “маслечко”, step by step

StepLanguageWordMeaning
1Russian-ечко-y, -ling; Forms diminutive adverbs, usually...
2Ukrainian-це́y, -ling
3Ukrainian-коCreates diminutives of normally neuter nouns and adverbs, normally having a colloquial register
4Proto-Slavic-ьko—
Every word from Proto-Slavic -ьko →Every word from Ukrainian -ко →Every word from Ukrainian -це́ →