A soldier who, as the term is, sings out at the halberts. It is a point of honour in some regiments, among the grenadiers, never to cry out, become nightingales, whilst under the discipline of the cat of nine tails; to avoid which, they chew a bullet.
NIGHTINGALE
Meaning of NIGHTINGALE in English
Slang English vocab. Английский сленговый словарь. 2012