Sentence:  “And, ma′am,” he continued, “the laundress tells me some of the girls have two clean <WSD>tuckers</WSD> in the week: it is too much; the rules limit them to one.” / “I think I can explain that circumstance, sir. Agnes and Catherine Johnstone were invited to take tea with some friends at Lowton last Thursday, and I gave them leave to put on clean <WSD>tuckers</WSD> for the occasion.” 
Meaning of the word marked with <WSD> tags:  Lace or a piece of cloth in the neckline of a dress.