used or accepted as normal or average. Official unit of measuring something.

action of helping or doing work for someone. To maintain a piece of machinery so it runs well.

belonging to present. Movement of water in a river, or air in the sky.

relating to branch of medicine dealing with deformities of bones or muscles.

person who has had long experience in particular field. Person experienced through long service.

resulting from. Event, usually unusual or important; accident.

Having happened or been done before this time.

advantage or profit gained. Good results or effects, something advantageous. To have a good effect or be helpful.

take place.

Being what was wanted or needed. used to greet someone in polite or friendly way. Friendly greeting to someone who has arrived. To greet someone who has just arrived.

Condition limiting your ability to do something.

Disease or other medical problem. have significant influence on.

mathematical relationship in symbols.

used for emphasis with following adjective functioning as adverb. Thing that is not yet known or named.

action of showing something, or fact of being shown. To prove something to be true.