Cause/kɔːz/nounThe reason something happens or exists.His laziness is the cause of his failure. Often appears as...cause and effect cause for concern Definition 1 of 4Pro Tip 1/2Not Always Negative The word 'cause' does not imply a negative reason; it can be neutral or positive. A promotion was the cause of her joy. Pro Tip 2/2Discovering Relationships Understanding 'cause' helps identify relationships between events or situations. Poor diet is the cause of many health issues.