Where does “blackboard” come from?

I need to work with the etymology chain provided, but I notice it appears to contain repetitive entries (back/backboard cycling) without clear progression to older languages or roots. Given the constraints and the chain as stated, here's what I can construct: Blackboard comes from English black and English back, compounded to form a board used for writing. However, I should note that the chain you've provided seems incomplete or corrupted—it doesn't trace back beyond English, and the repetitive back/backboard entries don't show etymological progression. A proper etymology would typically trace English black and English back to their own origins in older languages (likely Germanic roots). Could you verify the chain data?

blackboard (English): A large flat surface, finished with black slate...

Definitions

  1. A large flat surface, finished with black slate...

Ancestry of “blackboard”, step by step

blackboard traces back through two separate lines of ancestry.

via English board

StepLanguageWordMeaning
1EnglishboardA relatively long, wide and thin piece of any...
2Englishboardridersurfer
3EnglishriderOne who rides, often on a horse or a motorcycle;...
4Middle EnglishridereAlternative form of ryder
5Middle EnglishryderA rider or equestrian; one who rides a horse; A...
6Old Englishrīdererider, knight
7Old Englishrīdanto ride
8Proto-West Germanicrīdanto ride
9Proto-Germanicrīdanąto ride
10Proto-Indo-Europeanrēydʰ-
11Proto-Indo-Europeanh₂er-to fit, to fix, to put together

via English black

StepLanguageWordMeaning
1EnglishblackAbsorbing all light and reflecting none; dark and...
2Middle EnglishblakeAlternative form of blak
3Old Englishblācshining, white, pale; bleak, pale, pallid, wan,...
4Old English-ianForms verbs from nouns and adjectives
5Old English-ōjan
6Proto-West Germanic-ōnCreates denominative verbs from nouns; Creates...
7Proto-Germanic-ōnąCreates denominative verbs from nouns; Creates...
8Proto-Indo-European-eh₂yétiCreates iterative/ frequentative/ intensive...
9Proto-Indo-European-yétiCreates intransitive, often deponent,...
10Proto-Indo-Europeanyé-
11Chichewaiyehe, she

Words derived from “blackboard

Every word from Proto-Indo-European h₂er-