Question

What does 'Ergo' mean? Why does Launcelot use this word?​

Answer 1

Definition. ERGO. Euthanasia Research & Guidance Organization. ERGO.

Launcelot uses high-sounding words in order to confuse his father and disguise his own identity (he mentions intending to trick his father, since his father is half blind and clearly doesnt recognize his own son at first).

Answer 2

~Ergo means therefore in latin.

~Launcelot uses high-sounding words in order to confuse his father and disguise his own identity