To think or consider about something over time.

Note in a book, etc. giving source of information. provide book or article with citations of sources of information.

For a reason.

band of colours, as seen in rainbow, produced by separation of components of light. The wavelengths of colors from red to violet.

picture or diagram made with pencil, pen. To get closer to or approach something or someone. (Of 2 teams) to finish a game with the same score.

having become yellow. To turn yellow, often due to aging.

used for emphasis with following adjective functioning as adverb. thing that is unspecified or unknown.

in way that is not habitual or common.

Act of keeping in reserve.

matter. Substances from which a thing is made.

constituting or presenting problem. thing that constitutes problem.

person who is studying or has expert knowledge of one or more of natural or physical sciences. People who are trained in a science.

able to stick fast to surface or object. substance used for sticking objects or materials together.

Hiding your true character to mislead. To hide something so that it cannot be seen.

body's relative mass or quantity of matter contained by it, giving rise to downward force. Heavy metal objects that are lifted for exercise. hold something down by placing heavy object on top of it.