a large group of people or things; a regular order or arrangement; in maths: a series of figures. similar to another thing, so that it is reasonable to compare them the state of being awake, able to hear, see, and think a noise or something that stops you from continuing what you were doing a substance, especially a gas, that goes into the air a system for organizing people or things according to their importance something or someone that is added or included an opinion that you form based on information you already have the chance that something might happen size or importance concerning mathematics the process by which people or animals move to another place a prefix meaning 'not', e.g. non-alcoholic a set of written signs or shapes that are used in music or mathematics on or around something happening regularly, but not frequently a system or piece of equipment that is used to get information movement in a circle around a central point at the same time as how true something is