commit (something) to memory

to make yourself remember something.

I haven't got a pen to write down your phone number - I'll just have to commit it to memory.

• ruffle someone's feathers
• rule of thumb
• rule out
• rule out something
• rule someone with a rod of iron
• rule the roost
• rule with a rod of iron
• rum do
• rumpy-pumpy
• run across
• run across someone
• run across something
• run a fever
• run afoul of
• run afoul of someone
• run afoul of something
• run after
• run after someone
• run a mile
• run amok
• run and run
• run an errand
• run an eye over
• run an eye over something
• run around