Arising from the application of Optimality Theory (OT) to issues of language acquisition. the term "stratum" may represent (i) a single constraint. and therefore the strict ranking proposed by standard OT. as shown especially in research using data of the target language. https://www.nacrack.com/flash-pick-7-5ft-Heavy-Duty-Gold-Metal-Round-Wedding-Arch-Photo-Backdrop-Stand-top-grab/