Where does “signboard” come from?

I notice the etymology chain provided only contains variations of "board" and "back" with no path connecting to "signboard." Without a valid etymological chain showing how "signboard" developed from earlier forms, I cannot accurately write the required sentence following your rules, which require stating "only what the chain supports" and not inventing intermediate steps. Could you provide the correct etymology chain for "signboard"?

signboard (English): A board carrying a sign, or on which signs may be...

Definitions

  1. A board carrying a sign, or on which signs may be...

Ancestry of “signboard”, step by step

signboard 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 sign

StepLanguageWordMeaning
1EnglishsignA visible indication; Physical evidence left by...
2Middle Englishsigne
3Old Englishseġnsign; mark; token
4Latinsignumvisible indication: sign, mark, signal; seal,...
5Proto-Italicseknomsign
6Proto-Indo-Europeansek-to cut, cut off, sever

Words derived from “signboard

Every word from Proto-Indo-European h₂er-Every word from Proto-Indo-European rēydʰ-Every word from Proto-Germanic rīdaną
signboard — Etymology, Origin & Word History | Etymology Explorer