flex

Concise Oxford English Dictionary © 2008 Oxford University Press:
flex1

▶verb

• 1 bend (a limb or joint).

• 2 contract or tense (a muscle).

• 3 warp or bend and then revert to shape.

• 4 (as adj. flexed) Archaeology relating to or denoting the practice of burying a corpse with the legs drawn up under the chin.

– origin C16: from L. flex-, flectere ‘bend’.

Concise Oxford English Dictionary © 2008 Oxford University Press:
flex2

▶noun Brit. a flexible insulated cable used for carrying electric current to an appliance.

– origin early 20th cent.: abbrev. of flexible.