To think or consider about something over time.

A location on a map. To cite a piece of research in speech or writing.

for reason that.

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

Image made of pencil lines, or on a screen. To get closer to or approach something or someone. To create an image using pen or pencil and paper.

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.

careful use of resource.

matter. Supplies or data needed to do certain things.

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.

Having the ability to be glued to something. A substance used for gluing one thing to another.

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. Metal object to measure how heavy something is. hold something down by placing heavy object on top of it.