n. a possible explanation of why something exists or how something happens using experiments or ideas, but which is not yet proven ("Other scientists are debating his theory about the disappearance of dinosaurs.")
ad. having a large distance between two opposite surfaces ("The wall is two meters thick."); having many parts close together ("The forest is very thick."); almost solid, such as a liquid that does not flow easily; opposite thin
n. that which is measured in minutes, hours, days and years; a period that can be identified in hours and minutes and is shown on a clock; a period when an event should or will take place