Real Dictionary

mace
countable noun: A mace is an ornamental stick carried by an official or placed somewhere as a symbol of authority.
uncountable noun: Mace is a spice, usually in the form of a powder, made from the shell of nutmegs.
uncountable noun: Mace is a substance that causes tears and sickness, and that is used in sprays as a defence against rioters or attackers.

Mace in American English
a chemical compound, prepared for use in aerosol containers, that has the combined effect of a tear gas and a nerve gas, temporarily stunning its victims

mace in American English 1
a heavy medieval war club, often with a spiked, metal head
noun: a clublike armor-breaking weapon of war, often with a flanged or spiked metal head, used chiefly in the Middle Ages
noun: a nonlethal spray containing purified tear gas and chemical solvents that temporarily incapacitate a person mainly by causing eye and skin irritations: used esp. as a means of subduing rioters

mace in American English 2
a spice, usually ground, made from the dried outer covering of the nutmeg
noun: a spice ground from the layer between a nutmeg shell and its outer husk, resembling nutmeg in flavor
transitive verb: to attack with Mace spray

Mace in British English
noun: a liquid causing tears and nausea, used as a spray for riot control, etc
verb: to use Mace on

mace in British English 1
noun: a club, usually having a spiked metal head, used esp in the Middle Ages

mace in British English 2
noun: a spice made from the dried aril round the nutmeg seed