Synechdoche

This word (straight from greek: συνεκδοχή , simultaneous understanding) will never stick in my head.

It's a type of metaphor, in which parts stand for wholes, or vice versa.

Examples ripped from wikipedia

• Fill him full of lead.
• The smack of leather on willow
• The gray-beard and the long-hair
• The city posted a sign
• Put it on plastic
• A fresh pair of hands
• What sort of coke do you have?