article, counter for articles, clauses, paragraphs, etc., twig, ray of light
條 centers on long, slender, separate items: a twig, a ray of light, or a distinct article or clause in a document. The counter sense follows naturally from counting such individual items.
條 is the older form of 条. It combines 木 (tree) with 攸, which likely contributed the sound and the idea of something long and slender, like a twig. The modern simplified form 条 drops the 攸 component.
The left side 木 is a tree, and the right side 攸 looks like a person with a stick. Picture a person holding a long, slender twig broken from the tree, counting each twig as a separate article.
For ジョウ, imagine a long twig being used as a ruler to measure a row of articles: the row of articles is like a 'row' (ジョウ) of items, and the twig helps keep them in line.