What is "welsh hook"

Welsh \Welsh\, a. [AS. w[ae]lisc, welisc, from wealh a stranger, foreigner, not of Saxon origin, a Welshman, a Celt, Gael; akin to OHG. walh, whence G. w["a]lsch or welsch, Celtic, Welsh, Italian, French, Foreign, strange, OHG. walhisc; from the name of a Celtic tribe. See Walnut.] Of or pertaining to Wales, or its inhabitants. [Sometimes written also Welch.]

Welsh flannel, a fine kind of flannel made from the fleece of the flocks of the Welsh mountains, and largely manufactured by hand.

Welsh glaive, or Welsh hook, a weapon of war used in former times by the Welsh, commonly regarded as a kind of poleax.
--Fairholt.
--Craig.

Welsh mortgage (O. Eng. Law), a species of mortgage, being a conveyance of an estate, redeemable at any time on payment of the principal, with an understanding that the profits in the mean time shall be received by the mortgagee without account, in satisfaction of interest.
--Burrill.

Welsh mutton, a choice and delicate kind of mutton obtained from a breed of small sheep in Wales.

Welsh onion (Bot.), a kind of onion ( Allium fistulosum) having hollow inflated stalks and leaves, but scarcely any bulb, a native of Siberia. It is said to have been introduced from Germany, and is supposed to have derived its name from the German term w["a]lsch foreign.

Welsh parsley, hemp, or halters made from hemp. [Obs. & Jocular]
--J. Fletcher.

Welsh rabbit. See under Rabbit.

A Welsh hook is a type of polearm. A halberd-like weapon with a hook on the back, and gained it name due to its prevalence among the Welsh soldiers during the medieval wars against the English. It appears to have been derived from an agricultural implement known as a forest-bill (or a long hedging-bill), with the addition of a hook on the back and a spike on the front.