The Collaborative International Dictionary of English v.0.48:
Saker \Sa"ker\ (s[=a]"k[~e]r), n. [F. sacre (cf. It. sagro, Sp.
& Pg. sacre), either fr. L. sacer sacred, holy, as a
translation of Gr. "ie`rax falcon, from "iero`s holy, or more
probably from Ar. [,c]aqr hawk.] [Written also sacar,
(a) A falcon (Falco sacer) native of Southern Europe and
Asia, closely resembling the lanner.
Note: The female is called chargh, and the male
charghela, or sakeret.
(b) The peregrine falcon. [Prov. Eng.]
2. (Mil.) A small piece of artillery. --Wilhelm.
On the bastions were planted culverins and sakers.
The culverins and sakers showing their deadly
muzzles over the rampart. --Hawthorne.