Where does “walking school bus” come from?

walking school bus (English) comes from English walking, from English -ing, from Old English -ing, from Old English -tūn, from Old English tūn, from Proto-West Germanic tūn, from Proto-Germanic tūną, from Gaulish dunum — smoke; mist, haze.

Ancestry of “walking school bus”, step by step

walking school bus traces back through two separate lines of ancestry.

via English walking

StepLanguageWordMeaning
1Englishwalkingpresent participle of walk; Incarnate as a human;...
2English-ingUsed to form gerunds, a type of verbal nouns,...
3Old English-ingForming nouns from verbs, indicating action,...
4Old English-tūnhomestead, village, town
5Old Englishtūnenclosure, yard; place; dwelling
6Proto-West Germanictūnfence
7Proto-Germanictūnąfence; enclosure
8Gaulishdunumfort; hill, hillfort
9Proto-Celticdūnomstronghold, rampart
10Proto-Indo-Europeandʰewh₂-smoke; mist, haze

via English school bus

StepLanguageWordMeaning
1Englishschool busA bus which carries children to school
2EnglishschoolA group of fish or a group of marine mammals such...
3Middle Englishscoleschool
4Old Englishscōlplace of education
5Proto-Germanic*skōlu
6LatinscholaLeisure time given to learning; schooltime,...
7Ancient Greekσχολήleisure, free time; rest; that in which leisure...
8Proto-Hellenicskʰolā́
9Proto-Indo-Europeansǵʰ-h₃-léh₂
10Proto-Indo-Europeanseǵʰ-to hold; to overpower
Every word from Proto-Indo-European dʰewh₂-Every word from Proto-Celtic dūnomEvery word from English -ing