A Henry
An uncommon British slang term for an 1/8th measure of something, i.e. Marijuana (£20 worth).

Can be used to disguise the meaning of the conversation when around dissaproving parties.

Word usage is in reference to the British Monarch Henry the 8th.
Stoner 1: Yo, we gettin a Henry tonight?
Stoner 2: Ye man, if I can scrape the loot together.
Stoner 1: If you can't I'll just get a mench blad