very serious or severe; in maths, an angle < 90 degrees packed together; closely united; small coming together a problem; a fault not standard or normal; in statistics: the difference between one of a set of values and some fixed value, usually the mean of the set. a drawing intended to explain how something works to fix something inside something else a rough calculation; an opinion a part of a whole. a shared boundary between two persons or systems through which information is communicated. the study of the forms and structures of plants, animals and words not in a line energy that is radiated or transmitted in the form of rays, waves or particles. a line that seperates; a point of parting; a gap enough the study of a system, such as the system of words in a sentence by that means; because of that hot and humid; near to the equator sound; just; well-founded a line going up/down; not horizontal