For some reason I tend to confuse ARAL with URAL, but today I got to see them both together. Maybe this will help.
"Hoist by his own petard" (blown up by his own bomb) is a phrase often used incorrectly. Mostly I hear it, "hoist
on his own petard" meaning "strung up on his own flagpole." But
hoist means
blown up and
petard means, as Bonnie says, "explosive device." The expression comes from
Hamlet. I seem to remember it refers to Rosencrantz and Guildenstern with whom Hamlet gets even for their spying. There's no charge for today's lecture.
