What is the meaning of Galler?

One who or that which galls.

Person who trains gamecocks.

a grid, a lattice, bars; a pattern like XXX or ||| formed by several long, more-or-less rigid objects

a grid (of an electronic vacuum tube)

a Gaul; a person from the Gaul era

impersonal subjunctive of gallu

impersonal imperative of gallu

Source: wiktionary.org