British

a place that contains many interesting or valuable objects.

We found a shop that was a real Aladdin's cave of beautiful antiques. (often + of)

• matter of record
• matter of something
• matter of time
• max out
• max yourself out
• may as well
• may as well do something
• May the best man win.
• mea culpa
• meal ticket
• mealy-mouthed
• mean business
• means to an end
• mean well
• measure up
• measure up to
• measure up to someone
• measure up to something
• meat-and-potatoes
• meat and potatoes
• meat and two veg
• medallion man
• medium-term
• meet halfway
• meeting of minds