from
The Collaborative International Dictionary of English v.0.48
Guerrilla \Guer*ril"la\, n. [Sp., lit., a little war, skirmish,
dim. of guerra war, fr. OHG. werra discord, strife. See
{War}.]
1. An irregular mode of carrying on war, by the constant
attacks of independent bands, adopted in the north of
Spain during the Peninsular war.
[1913 Webster]
2. One who carries on, or assists in carrying on, irregular
warfare; especially, a member of an independent band
engaged in predatory excursions in war time.
[1913 Webster]
Note: The term guerrilla is the diminutive of the Spanish
word guerra, war, and means petty war, that is, war
carried on by detached parties; generally in the
mountains. . . . A guerrilla party means, an irregular
band of armed men, carrying on an irregular war, not
being able, according to their character as a guerrilla
party, to carry on what the law terms a regular war.
--F. Lieder.
[1913 Webster]