Emily Dickinson Lexicon

SLOUGH, n. [slou; Sax. slog; W. yslwç, a gutter or slough, from llwç, a lake.]

1. A place of deep mud or mire; a hole full of mire. – Milton.
2. [pron. sluff.] The skin or cast skin of a serpent. [Its use for the skin in general, in Shakspeare, is not authorized.]
3. [pron. sluff.] The part that separates from a foul sore. – Wiseman. The dead part which separates from the living in mortification. – Cooper.