Emily Dickinson Lexicon

CLEW, n. [Sax. cleow, cliwe; D. kluwen; G. kloben; L. globus. The word signifies a ball or a lump. In Welsh, clob is a knob or boss; clwpa is a club or knob; clap is a lump; all from roots in lb; llob, a lump, a lubber.]

1. A ball of thread. – Spenser.
2. The thread that forms a ball; the thread that is used to guide a person in a labyrinth. Hence, any thing that guides or directs one in an intricate case. – Watts.
3. The lower corner of a square sail, and the aftmost corner of a stay sail. – Mar. Dict.