"Full absorbency" means the ability of something, like a material or a product, to soak up or take in a maximum amount of liquid or moisture. Full definition
It felt much more saturated the first morning so I assume we reached full absorbency after the second wash. (themamaknows.com)
This diaper will reach full absorbency after 10 washes, but it can be used after 2 washes. (diaperjunction.com)
The natural cotton oils present in unbleached cotton must be washed off in those first several hot washes before full absorbency is reached. (greenmountaindiapers.com)